レッスン35 · ステージ3: 予定・依頼・比較
不必要：don't have to / needn't
中級No obligation: don't have to / needn't
形と使い方
don't have to / don't need to / needn't + 動詞 — する必要がないこと
1.形
何かが必要ない（してもいいけれど、しなくていい）と言うには、don't have to、don't need to、needn't + 原形を使います。
| 形 | 例 | メモ |
|---|---|---|
| don't / doesn't have to | You don't have to pay. · Thu doesn't have to work on Sundays. | いちばんよく使う；どんな場面でも使える |
| don't / doesn't need to | We don't need to hurry. | don't have to と同じ意味；to を忘れずに |
| needn't | You needn't wait for me. | to も -s もつかない；少しかしこまった言い方で、主にイギリス英語 |
| didn't have to / didn't need to | We didn't have to queue. | 過去 |
| won't have to / won't need to | We won't have to take the ferry any more. | 未来 |
needn't は助動詞のように働きます（-s も to もつかない）：He needn't come。ふつうの動詞としての need は to と do を使います：He doesn't need to come。2つを混ぜないようにしましょう（needn't to や doesn't need come は不可）。
2.どんなときに使うか
1. 任意のこと — したければしてもいい
You don't have to come with me. I can go alone.
一緒に来なくていいよ。一人で行けるから。
It's Sunday tomorrow, so I don't have to get up early.
明日は日曜日だから、早起きしなくていい。
2. 状況のおかげで、何かをしなくて済む
Thu doesn't have to pay rent. She lives with her parents.
トゥーは家賃を払わなくていいんです。両親と住んでいるので。
The test is open-book, so you don't need to learn the dates by heart.
テストは持ち込み可なので、年号を暗記する必要はありません。
3. 「気をつかわなくていいよ」と伝える — 丁寧で親しみのある言い方
You don't have to bring anything. Just come!
何も持ってこなくていいよ。来てくれるだけでいいから！
You needn't worry. Everything is ready.
心配いりません。準備はすべて整っています。
You don't have to shout. I can hear you.
そんなに叫ばなくていいよ。聞こえてるから。（本当の意味：叫ぶのをやめて）
4. 必要かどうかたずねる
Do I have to bring my passport? — No, you don't.
パスポートを持っていく必要はありますか？ — いいえ、要りません。
Do we need to book? — No, you don't need to. Just walk in.
予約は必要ですか？ — いいえ、要りません。そのまま来てください。
3.don't have to か mustn't か
この2つは似て見えますが、意味はまったく違います：
| 意味 | |
|---|---|
| You don't have to tell him. | 彼に言う必要はない（言ってもいい）。 |
| You mustn't tell him. | 彼に言ってはいけない — 許されていない。 |
You don't have to pay for the drinks. They're free.
飲み物の代金は払わなくていいですよ。無料です。
You mustn't park here. It's for ambulances only.
ここに駐車してはいけません。救急車専用です。
簡単なテスト：「…でも、したければしてもいい」を付け加えられるなら don't have to。「禁止」という意味なら mustn't を使います。
4.過去のことを話す
過去では didn't have to か didn't need to を使います：必要なかった、という意味です。
The bus was almost empty, so we didn't have to stand.
バスはほとんど空いていたので、立たなくて済みました。
Lan didn't need to cook — her mum had made dinner.
ランは料理をする必要がなかった。お母さんが夕食を作ってくれていたから。
実際にやったけれど、結果的に必要なかった場合、イギリス英語では needn't have + 過去分詞 を使うことがあります。ふだんの会話では、単に didn't need to と言う人も多いです。
Oh, you needn't have bought milk — I got some this morning.
あ、牛乳は買わなくてもよかったのに。今朝買っておいたんだ。（買ったけれど、必要なかった）
5.よくある間違い
You mustn't pay for the drinks. They're free.You don't have to pay for the drinks. They're free.
必要ない → don't have to。mustn't は「禁止」です。
He don't have to work on Saturdays.He doesn't have to work on Saturdays.
he/she/it → doesn't。
She doesn't has to cook tonight.She doesn't have to cook tonight.
doesn't のあとは has ではなく have です。
You needn't to call me first.You needn't call me first.
needn't のあとに to はつけません。
You don't need bring anything.You don't need to bring anything.
don't need には to が必要です。
We haven't to wait.We don't have to wait.
have to の否定には don't を使います。
例文
- It's Sunday tomorrow, so I don't have to get up early.
- Thu doesn't have to worry about rent. She lives with her parents.
- We don't need to hurry. The film starts at nine.
- You don't have to take your shoes off. Come in!
