That's not necessary.

除了用No之外另一句較婉轉(zhuǎn)拒絕別人的常用句子是：”That’s not necessary.”(這不需要)。當(dāng)你想拒絕一些不太需要的商業(yè)服務(wù)，可以說：”That’s not necessary.”表示你不需要，假如別人堅(jiān)持替你做，而你也無所謂的話可說：”That’s not necessary but if you do, it would be nice.”(這并不是必須的，但如你真的要做，也是不錯(cuò))。 除了That’s not necessary. 外，也可用Please don’t bother. (不要打擾)或You don’t have to. / You don’t need to. / That’s no need. 都是不需要的意思。

對(duì)話

A: I'll give you a call after I arrive in San Francisco.

B: That's not necessary. Long distance charges are expensive. Just send me an email.

A: I'm afraid I won’t have my PC set up that soon.

B: Come on, you can find internet bars and cafes all over San Francisco.

A: That’s true.

甲：我到達(dá)舊金山后會(huì)給你電話。

乙：這不必了，長途電話費(fèi)很貴，給我電子郵件便可。

甲：恐怕我來不及安裝好計(jì)算機(jī)。

乙：拜托，舊金山到處都可找到網(wǎng)絡(luò)咖啡店。

甲：對(duì)。

叫人家不必做一件事，除了說：It is not necessary (for you) to do that，你當(dāng)然還可以用名詞need字：There is no need (for you) to do that。用need做動(dòng)詞則怎樣說呢? Need做動(dòng)詞，用法比較特別。首先，它可以和普通動(dòng)詞一樣有字尾變化，例如： You need. / He needs to do that.(你/他必須這樣做)、You don’t . / He doesn’t need to do that. (你/他不必這樣做)、Do you / Does he need to do that?(你/他要這樣做嗎?)

但在否定或疑問句里，need字有時(shí)會(huì)做輔助動(dòng)詞(auxiliary verb)用，和must、should等差不多，例如You / He need not do that. (=You don’t. / He doesn’t need to do that.)、Need you / he do that? (=Do you / Does he need to do that?) 這兩句雖然是說現(xiàn)在的事，但need和he連用也不必加s。

說過去，You did not need to do that. 是說‘你不必那樣做’，做了沒有未見說明，need是主要?jiǎng)釉~;You need not have done that. 也是說‘你不必那樣做’，但你做了，need是輔助動(dòng)詞。

還有一個(gè)字是必須談?wù)劦模簄ecessarily。這是個(gè)副詞(adverb)，和形容詞(adjective) necessary　同源而形似，但意思不同，解作‘必然’，常用于否定句，not necessarily即‘未必’，例如：(1) “He’ll lose.” “Not necessarily.”　( ‘他會(huì)輸。’ ‘未必。’) (2) Learned people do not necessarily prosper.(有學(xué)問未必就會(huì)發(fā))。