跟读练习: IAM - 通过视频学习英语口语

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Hey everyone!

Today I'd like to walk you through AWS Identity and Access Management, or IAM.

We'll take a look at how IAM works, how it controls access to AWS resources, and some common security best practices.

Rather than thinking of IAM as just a place to create users, I want you to think of it as the authorization control plane for AWS.

As engineers, we work with IAM all the time, even when we're not opening the IAM console.

EC2 instance roles, Lambda execution roles, CI, CD deployments, and cross -account access all depend on it.

One quick detail before we start.

IAM is a global service, even though the AWS services receiving requests may be regional.

All right, let's start with the problem IAM is designed to solve.

Two, what problem does IAM solve?

Okay, let's take a look at the three columns here.

Before IAM, IAM itself, and the outcome.

On the left, imagine an environment where developers share credentials, applications store static access keys,

administrators review access manually, and delegating permissions across teams is difficult.

That's hard to secure and even harder to scale.

Those weren't the best times, right?

In the middle, IAM gives us a central way to define policies, use roles and federation, issue temporary credentials,

and apply guardrails with auditing.

On the right, those capabilities help us achieve least privilege, cross -account access, automated deployments, and traceable API calls.

Of course, IAM doesn't automatically make our permissions secure.

We still have to design them correctly.

Here's a real -world example at the bottom.

Basically, when a workflow runs, it can request an OIDC token and use that token to authenticate with AWS.

Now, AWS checks the role's trust policy to make sure the workflow is allowed to assume that role.

if everything checks out aws sts provides temporary credentials

which the workflow can then use to deploy resources based on the permissions assigned to that role

and here's the important part we don't need to store any long -lived aws access keys in github

so essentially we're moving away from permanent credentials and toward a more secure approach where access is temporary and controlled.

03. What is IAM?

All right, so what exactly is IAM?

At a high level, IAM helps control who can do what in AWS, on which resources, and under which conditions.

Look at the three blocks across the top.

First, principles.

These are the identities making requests.

IAM users, assumed roles, federated identities, and AWS services.

Second, policies.

These are the authorization rules.

The slide mentions identity -based policies, resource -based policies, trust policies,

permissions boundaries, and service control policies, or SCPs.

Third, STS and sessions stands for AWS Security Token Service,

which issues temporary credentials, and sessions can carry tags used in authorization.

Now look at the middle statement, where IAM sits.

IAM is the Global Identity and Permissions Control Plane.

When a request reaches a target AWS service, AWS evaluates the relevant authorization controls and either allows or denies the operation.

And the three labels at the bottom matter too.

Managed means AWS runs the underlying IAM infrastructure.

Global means IAM identities are associated with AWS accounts, not individual VPCs.

API first means we can manage users, roles, and policies through APIs and infrastructure as code, including Terraform.

04. How IAM works.

Request evaluation.

Alright, so now that we understand the basics of IAM, let's take a look at what actually happens when someone makes a request to AWS.

If you look at the diagram, we have four steps here.

First, we have the principle.

Basically, this is whoever or whatever is making the request.

It could be a user, an application, or an AWS service.

The request is typically signed using AWS credentials, such as an access key.

And if we're using temporary credentials, there's also a session token involved.

Now, moving to step two, we have the request context.

This is where AWS looks at what the principal is actually trying to do.

For example, which API action is being requested?

Which resource are we trying to access?

And depending on the request, AWS can also consider additional information like resource tags, source IP addresses, MFA, or organization membership.

So essentially, AWS needs to understand not just who's making the request, but also what they're trying to do and under which conditions.

All right, now step three is probably the most important one, policy evaluation.

And here's the key rule to remember.

An explicit deny always takes precedence over an allow.

So even if a role has permissions to perform an action, another policy might still block it.

For example, that could be an SCP, a permissions boundary, or a session policy.

Now, if there's no explicit deny, AWS checks whether the request has the necessary permissions.

If there's an applicable allow and no other restrictions block it, the request can proceed.

Otherwise, it's denied by default.

That's what we call an implicit deny.

Now, if you look at the bottom of the slide, there's one important thing I want you to remember.

Whenever you're troubleshooting an IAM permission issue, start with four simple questions.

Who's making the request?

What action are they trying to perform?

Which resource are they accessing?

And under what conditions?

If you can answer those four questions, you're already in a much better position to understand why AWS is allowing or denying the request.

All right, so now that we've covered how IAM evaluates requests, let's move on to the core components that make all of this work.

05. Core Components All right, so now that we've seen how IAM evaluates requests,

let's take a closer look at the main components that make all of this work.

As you can see on the slide, we have eight components here.

So let's quickly walk through each one.

First, we have IAM users.

Basically, an IAM user represents an individual identity within an AWS account.

Now, IAM users can have long -term credentials such as passwords or access keys.

But here's the thing.

In modern AWS environments, we generally try to avoid using permanent access keys, especially for applications and automated workloads.

Instead, we prefer roles and temporary credentials.

Next, we have groups.

Groups are pretty straightforward.

They allow us to organize IAM users and assign permissions to multiple users at once.

For example, instead of attaching the same policy to 10 different users, we can create a group and manage those permissions in one place.

All right, moving on to roles.

And this is probably one of the most important components in modern AWS architectures.

A role is an identity that can be assumed by an authorized principle.

For example, an EC2 instance, a Lambda function, a user from another AWS account,

or even a GitHub Actions workflow can use a role.

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Now, let's talk about policies.

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Policies are basically JSON documents that define permissions.

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They specify which actions are allowed or denied, which resources those actions apply to, and sometimes additional conditions.

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And as you can see, we have different types of policies, including identity -based and resource -based policies.

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Now, right below that, we have trust policies.

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And here's an important distinction.

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A trust policy defines who is allowed to assume a role.

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A permissions policy defines what that role is allowed to do once it's assumed.

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So, for example, a GitHub Actions workflow.

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Its actual permissions still depend on the policies and restrictions that apply to the role session.

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All right, next we have STS, or Security Token Service.

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STS is responsible for issuing temporary AWS credentials.

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Now, moving on to Access Analyzer.

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This is a really useful service from a security perspective.

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It helps us identify resources that may be accessible from outside our intended trust boundaries.

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It can also help us detect unused access and validate IAM policies.

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And finally, we have MFA and credential management.

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This is mainly about protecting human access, especially privileged users and the root account.

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MFA adds another layer of authentication, while proper credential management helps reduce the risks associated with long -lived access keys.

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Zero.

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All right, so now let's take a look at security.

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As you can see on the left side of the slide, we have a bad security practice.

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Basically, we're allowing a very broad trust relationship without properly restricting who can assume the role.

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Not exactly what we want in production, right?

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Now, on the right, we have a much better approach.

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And this is where the zero trust security concept comes in.

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The main idea is pretty simple.

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Never trust anyone by default.

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Instead, we explicitly define who can assume the role and under which conditions.

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Verify identities, restrict trust relationships, and follow the principle of least privilege.

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07. Real -world use cases.

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All right, so now let's take a quick look at some real -world use cases where IAM plays an important role in production.

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As you can see on the slide, we have several common scenarios.

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Healthcare workloads.

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Here, security and audibility are especially important.

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We use least privileged roles, CloudTrail for auditing, MFA, and controlled emergency access to protect sensitive environments and maintain separation of duties.

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For CI -CD pipelines, we typically use OIDC Federation with GitHub, GitLab, or Jenkins to assume deployment roles without storing permanent AWS credentials.

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For microservices, each service gets its own IAM role, with scoped access to resources like S3, SQS, SNS, or KMS.

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For data pipelines, services like

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Glue, EMR, and Lambda use dedicated roles with restricted S3 and KMS permissions.

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In cross -account environments, a shared tooling account can assume roles across different AWS accounts.

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And finally, for monitoring, we can provide read -only access to tools like Datadog using cross -account roles and external IDs where appropriate.

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So the main takeaway here is pretty simple.

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Regardless of the architecture, we want to avoid shared credentials, isolate permissions, and follow the principle of least privilege.

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8 .08, Pricing and Cost Optimization, General American Transcription.

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Let's switch to cost.

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The headline on this slide is important.

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IAM itself is usually not what drives a bill.

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But here's the thing.

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Some of the services we use alongside IAM can generate costs.

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For example, IAM Access Analyzer offers external access analysis at no additional charge,

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but features like unused access analysis and custom policy checks may incur charges.

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Now let's take a look at the example at the bottom left.

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Imagine we have 10 AWS accounts with 200 IAM roles and five CICD pipelines in each account.

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That's 2 ,000 roles and 50 pipelines in total.

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And the interesting part is that we don't pay for the IAM roles themselves or standard STS usage.

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Instead, the costs come from the security, monitoring, and networking services we enable around them.

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Now, moving over to the right, we have a few optimization strategies.

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We can use OIDC Federation instead of permanent access keys, reuse managed policies where appropriate,

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remove unused roles, and configure CloudTrail data events based on our actual auditing requirements.

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We can also use

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Access Analyzer to identify unnecessary permissions and improve lease privilege.

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And of course, we don't want to compromise security just to save money.

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The goal is to configure these services efficiently while maintaining the right level of protection.

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9. Reference Architecture Alright, so now let's put everything together and look at how it works in a real -world CICD architecture.

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As you can see on the slide, we have a pretty common deployment workflow using GitHub Actions, IAM, AWS STS, and Terraform.

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So let's walk through it from left to right.

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First we have GitHub Actions.

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When a pipeline starts, GitHub can generate an OIDC token containing information about the repository and branch.

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Next, we have the IAM role trust policy.

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This is where AWS verifies whether the workflow is allowed to assume the role.

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Now moving over to Terraform.

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Terraform uses those temporary credentials to deploy infrastructure changes.

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But remember, Terraform can only perform actions allowed by the role's permissions and other applicable security controls.

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Now, let's take a quick look at the bottom of the diagram.

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On the left we have S3, which stores the Terraform state.

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Access to that bucket is restricted to authorize roles.

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Next we have EKS, ECS, and Lambda, which represent the AWS services Terraform might deploy or update.

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Then we have CloudTrail, which records supported AWS API activity.

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And finally, CloudWatch provides monitoring through events and metrics.

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So essentially all these components work together to provide a secure and auditable deployment process.

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So essentially all these components work together to provide a secure and auditable deployment process.

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10 Production Best Practices Checklist general American transcription.

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Let's quickly go through some production best practices.

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So let's start with the top five.

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First, always prefer IAM roles and temporary credentials over permanent access keys.

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Second, make sure your trust policies are properly scoped.

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We want to explicitly control who can assume a role rather than allowing broad access.

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Third, follow the principle of least privilege.

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Fourth, implement security guardrails, such as SEPs, permissions boundaries, MFA, and controlled emergency access.

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And fifth, enable auditing and monitoring.

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Use CloudTrail to track IAM activity and configure alerts for potentially risky changes.

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Now, if you look at the bottom of the slide, we have three additional areas to consider.

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From a security perspective, protect their root account, enforce MFA, and use conditions and explicit deny policies where appropriate.

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For reliability, remember that IAM changes can take time to propagate,

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so we should avoid making unnecessary IAM changes during critical application operations.

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And finally, from an operations perspective, manage IAM policies through infrastructure as code.

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Use code reviews, validate policies, and follow consistent naming standards.

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Final recap.

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All right, so before we wrap up, let's quickly recap what we've covered today.

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We started by looking at what IAM is and why it's important for managing access to AWS resources.

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We learned how IAM evaluates requests, how policies work, and why an explicit deny always takes precedence over an allow.

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Then we looked at security best practices, including zero trust, least privilege, temporary credentials, and MFA.

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We also explored some real -world use cases and saw how OIDC CICD deployments without permanent AWS access keys.

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And finally, we discussed cost optimization, auditing, and production best practices.

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IAM isn't just about managing users and permissions.

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It's about building a secure, scalable, and auditable access model across AWS.

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And that's exactly what we want in production.

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Alright, that's everything I wanted to cover today.

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Thanks for watching!

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Thanks, everyone.

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I'm happy to take any questions.

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IAM 1

Daily ConversationWorking Adults

FOR YOU

本课的词汇与口语要点

视频中反复出现的词有：Iam, aws, role, access, permission。这段视频共有 211 个句子、2425 个单词可供跟读。讲话部分时长为 18:12。说话人语速平稳，每分钟约 133 个词，很适合跟读。只有 76% 的单词属于英语最常用的 3,000 词，词汇难度较高。

视频中的重点词汇

视频中 15 个值得学习的单词，附发音和释义：

单词	发音	释义
temporary 形容词	/ˈtɛmp(əˌɹ)ɛɹi/	暫時 /暂时
deny 动词	/dəˈnaɪ/	否認 /否认, 否定
slide 名词	/ˈslaɪ̯d/	滑梯
privilege 名词	/ˈpɹɪv.(ɪ.)lɪd͡ʒ/	特權 /特权
component 名词	/kəmˈpoʊ.nənt/	元件, 部件
principle 名词	/ˈpɹɪn.sɪ.pəl/	原理, 原則 /原则
token 名词	/ˈtoʊkən/	代幣 /代币, 籌碼 /筹码
resource 名词	/ɹɪˈzɔːs/	資源 /资源
define 动词	/dɪˈfaɪn/	界定
audit 名词	/ˈɔːdɪt/	檢查 /检查
pipeline 名词	/ˈpaɪpˌlaɪn/	管道, 管線 /管线
infrastructure 名词	/ˈɪnfɹəˌstɹʌkt͡ʃə/	基礎設施 /基础设施
architecture 名词	/ˈɑː.kɪˌtɛk.t͡ʃə/	建築 /建筑, 建築學 /建筑学
essentially 副词	/ɪˈsɛnʃəli/	本質上 /本质上, 基本上
monitor 名词	/ˈmɑ.nɪ.tɚ/	顯示器 /显示器

视频中出现的短语动词

单词	释义
check out 动词	退房
go through 动词	通過 /通过

值得反复跟读的句子

视频中简短而完整的句子，可以直接用在日常对话里：

Which resource are we trying to access?
That's what we call an implicit deny.
Let's quickly go through some production best practices.
Alright, that's everything I wanted to cover today.
I'm happy to take any questions.

视频中的语法

说话人最常用的结构，并附上视频中的原话：

结构	视频中的用法
被动语态 be + 过去分词 — 强调发生了什么，而不是谁做的	is designed · is allowed · are associated
现在完成时 have/has + 过去分词 — 过去发生但与现在仍有关联的事	we've covered · we've seen

需要注意的发音

说话人用了 19 次缩略和弱读形式，例如 we're, don't, we've。请按听到的简短形式来说。

“th” 音: authorization /ˌɔːθəɹaɪˈzeɪʃən/, authorize /ˈɔθəɹaɪz/, authenticate /ɔˈθɛn.tɪ.keɪt/, authentication /ɔːˌθɛntɪˈkeɪʃn̩/
“sh” 和 “zh” 音: essentially /ɪˈsɛnʃəli/, authorization /ˌɔːθəɹaɪˈzeɪʃən/, federation /ˌfɛdəˈɹeɪ̯ʃən/, optimization /ˌɑptəmaɪˈzeɪʃən/, evaluation /ɪˌvæljuˈeɪʃn̩/
长单词——注意重音位置: temporary /ˈtɛmp(əˌɹ)ɛɹi/, infrastructure /ˈɪnfɹəˌstɹʌkt͡ʃə/, architecture /ˈɑː.kɪˌtɛk.t͡ʃə/, essentially /ɪˈsɛnʃəli/, authorization /ˌɔːθəɹaɪˈzeɪʃən/

中文母语者容易读错的音：

/v/ — 不要读成 /w/，上齿轻触下唇: privilege /ˈpɹɪv.(ɪ.)lɪd͡ʒ/, evaluate /ɪˈvaljʊeɪt/, solve /sɒlv/, evaluation /ɪˌvæljuˈeɪʃn̩/, verify /ˈvɛɹɪfaɪ/
词尾辅音 — 要读清楚，后面不要加元音: slide /ˈslaɪ̯d/, privilege /ˈpɹɪv.(ɪ.)lɪd͡ʒ/, component /kəmˈpoʊ.nənt/, deployment /dɪˈplɔɪmənt/, resource /ɹɪˈzɔːs/
/r/ 和 /l/ 的区别: privilege /ˈpɹɪv.(ɪ.)lɪd͡ʒ/, principle /ˈpɹɪn.sɪ.pəl/, regardless /ɹɪˈɡɑɹd.lɪs/, explore /ɪkˈsploɹ/, correctly /kəˈɹɛk(t).li/

如何用这段视频练习

先完整听一遍视频，不要开口，记下不认识的单词。
用正常速度逐句跟读，每句重复到你的节奏与说话人一致为止。
录下自己的声音并与原声对比，特别注意 temporary, deny, slide 这类单词。

什么是跟读法？

跟读法 (Shadowing) 是一种有科学依据的语言学习技巧，最初开发用于专业口译员的培训，并由多语言者Alexander Arguelles博士普及。这个方法简单而强大：您在听英语母语原声的同时立即大声重复——就像是一个延迟1-2秒紧跟说话者的影子。与被动听力或语法练习不同，跟读法强迫您的大脑和口腔肌肉同时处理并模仿真实的讲话模式。研究表明它能显着提高发音准确性，语调，节奏，连读，听力理解和口语流利度——使其成为雅思口语备考和真实英语交流最有效的方法之一。

影子跟读法: 阅读完整分步指南 →

跟读练习: IAM - 通过视频学习英语口语

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