跟讀練習: The Most Confused Concepts in Engineering - 通過影片學習英語口語

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Think back to the last time when you were searching something on Google.

If you notice your browser bar, you may see something like this.

If we look carefully, we can see that the spaces are actually replaced by person 20, and question mark is replaced by person 3f.

The browser somehow transformed our query into something different.

Why?

Because the URLs are allowed to have only a limited number of characters, and in that character set, characters like space are not valid.

but it still needs to be sent, and therefore it is converted into something that belongs to the allowed character set.

This type of transformation of data from one form to another, for the purpose of storage or transmission, is called encoding.

And similar to this, the data can be encoded to other forms as well.

For example, the text hello can be converted into many different forms, for example binary, hexadecimal, or base64.

The encoding is not only limited to transmitting data, but has other uses as well.

For example, if you work on the front-end with CSS, you might have seen the color codes which have the RGB values.

Those values are usually written in hexadecimal for its compact nature.

In decimal, the same value would look like this.

Similarly, in HTML, you may have seen the image stack to add images to your page, which refer to the URL where the image resides.

While this is fine for large images, The lighter images can be directly embedded in the Base64 format via HTML or CSS to save a network call.

The key point to understand here is that encoding is reversible.

For example, anyone who sees person 20 can decode it back to a space.

It's about data representation, not security.

And speaking of security, let's talk a bit about hashing.

Whenever you create an account online, your password is never stored in plain text.

Instead, it's converted into a fixed-length string of characters, which could look like this.

From this string alone, it is impossible to construct the original password again, and this type of transformation is possible by a process called hashing.

Hashing is a process where you convert data into another irreversible form by the use of a hashing algorithm, which does some complex math behind the scenes to achieve this.

So when you login, the password that you enter is hashed again and compared with the hash that exists in the system.

If they are same, the login is successful.

Hashing is defined by three main things.

First, that it is one way.

You can't reverse a hash to retrieve the original input.

Second, it is deterministic.

The same input always produces the same hash.

And third, is that it is always of fixed length.

So, no matter how long your password is, the hash always will be of the same size.

Hashing is not only used in passwords, but it has other applications as well.

For example, in file downloads.

If the downloaded file is corrupt, its hash would be different from the original file.

Whereas if the downloaded file is intact, its hash would be the same as original file.

If you're intrigued by hashing, check out my deep dive video on what is hashing, to learn about different hashing algorithms and hash collisions.

Now, what if you need that one-way transformation to be two-way, but only for some selected people or systems?

That's where encryption comes in.

Imagine that you have a top-secret document on your computer.

Anyone with access to your machine can open and read it.

Encryption provides a way to transform your document or data into a form

that can only be reversed by the use of a key.

So whoever holds the key can access the data.

If someone tries to open it without the key, they'll only see gibberish.

Let's take a simple example of encryption, one that dates back over 2000 years.

Julius Caesar used a basic encryption technique to protect messages of military importance.

It's now famously known as Caesar's cipher, or the shift cipher.

The idea?

Shift each letter of the message by a fixed number of positions in the alphabet.

say 3.

So if we take the word hello and shift each letter by 3, H becomes K, E becomes H,

L becomes O, the next L also becomes O, and O becomes R.

That gives us KHOOR.

To anyone who intercepts this message without knowing the shift, it looks like gibberish.

But if the recipient knows that each letter was shifted by 3, they can just reverse the shift and decrypt the message back to hello.

This kind of encryption is laughably easy to crack today, especially with modern computers.

But it beautifully illustrates the core idea.

The message is only readable to someone who has the key.

Modern encryption is, let's just say, a bit more advanced.

Instead of the letter shifts, we now use complex mathematical algorithms that are designed to be unbreakable by brute force, at least with current computers.

Quantum computing might change that, but that's a topic for another video.

Take WhatsApp, for example.

Every message that you send is encrypted on your device before it even leaves your phone.

If someone tries to snoop on the network, all they see is garbled nonsense.

Only the person that you are messaging with the matching decryption key can turn that noise back into actual words.

That's encryption, locking your data in such a way that only the right key can unlock it.

To put it all together, encoding is like translating data into another format so computers can store or transmit it properly.

It's not about secrecy, it's about structure and readability.

And yes, it is completely reversible.

Some examples are UTF-8, binary, hexadecimal, and base64.

Hashing takes your data and runs it through a special formula to create a unique, fixed-length code.

This code doesn't reveal the original data, and you cannot convert it back.

That's why it's perfect for safely storing passwords or checking if a file has been tampered with.

If the data changes, the hash changes too.

Encryption is about confidentiality.

It transforms your data into something unreadable, but only temporarily.

Because unlike hashing, encryption is reversible if and only if you have the right key.

That's how secure messaging apps like WhatsApp protect your conversations even from their own servers.

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關於本課

在本課中，您將學習關於資料轉換的基本概念，包括編碼、雜湊和加密。通過回顧這些術語及其應用，您可以提高自己的英語理解能力，同時增強專業詞彙。這些知識對於工程和電腦科學領域尤為重要。通過舉例和簡單的解釋，您不僅會掌握基本概念，還可以在實際應用中使用這些知識。

關鍵詞彙和短語

編碼 (encoding)：將資料轉變為可儲存或傳輸形式的過程。
雜湊 (hashing)：將資料轉換為不可逆形式的一種方法。
加密 (encryption)：將資訊轉換為只能通過金鑰逆向解讀的形式。
字元集 (character set)：用於編寫URL或其他文本的字元的集合。
十六進位制 (hexadecimal)：一種常用的數碼錶達方式，尤其在CSS中。
固定長度 (fixed length)：雜湊值的長度不受原始資料的影響，總是相同的。
金鑰 (key)：在加密中用於解碼資訊的重要資訊。
錯誤檢查 (error checking)：驗證下載檔案是否完整的過程。

練習技巧

為了提高您的英語發音和聽力理解，建議您進行英語影子跟讀。在觀看這段影片時，注意演講者的語速和語調，按照以下步驟進行練習：

暫停並重復：每當您聽到一個新的概念時，暫停影片並試著用英語複述它。這可以幫助您鞏固理解。
關注語調：注意演講者在關鍵點上的語調變化，如強調“雜湊”或“加密”時的語氣，這對於掌握英語的自然表達非常重要。
使用
看YouTube學英語的方法來練習：您可以反覆觀看相同的片段，直至對內容熟悉。
在影片播放速度上做調整：有時候，將速度調慢可以更清晰地聽到發音，從而增強提高英語發音的能力。
定期保持練習：與您的學習夥伴合作使用這些技巧，形成shadowing site或shadow speech的能力，以便不斷提升。

影片中的語法

說話人最常用的結構，並附上影片中的原話：

結構	影片中的用法
被動語態 be + 過去分詞 — 強調發生了什麼，而不是誰做的	are actually replaced · are allowed · be sent
定語從句 who / which + 從句 — 補充說明人或事物	codes which have · anyone who sees · anyone who intercepts

什麼是跟讀法？

跟讀法 (Shadowing) 是一種有科學依據的語言學習技巧，最初開發用於專業口譯員的培訓，並由多語言者Alexander Arguelles博士普及。這個方法簡單而強大：您在聽英語母語原聲的同時立即大聲重複——就像是一個延遲1-2秒緊跟說話者的影子。與被動聽力或語法練習不同，跟讀法強迫您的大腦和口腔肌肉同時處理並模模擬實的講話模式。研究表明它能顯著提高發音準確性，語調，節奏，連讀，聽力理解和口語流利度——使其成為雅思口語備考和真實英語交流最有效的方法之一。

影子跟讀法: 閱讀完整分步指南 →

跟讀練習: The Most Confused Concepts in Engineering - 通過影片學習英語口語

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關於本課

關鍵詞彙和短語

練習技巧

影片中的語法

什麼是跟讀法？