代替與省略
英語中，為了避免不必要的重複，經常用so, not, to, do, does 代替前麵出現的動詞或相關內容。
如：He translated the article better than I did. (did代替wrote it)
— Do you think she is clever?
— I think so. (so代替 she is clever)
(1) 從上兩例中看出，do / does / did 代替動詞。
(2) "so 與 not" 代替某個詞、短語、句子等，通常用於hope, think, believe, expect, suppose, be afraid, fear, imagine, etc後作賓語。
E.g. — Is it correct?
— I'm afraid not. (not correct)
(3) "to" 用作不定式，常跟隨下列動詞：want, mean, hope, expect, refuse, seem, intend, be, afraid, etc.
E.g. I asked him to go to the party, but he refused to. (go to the party)
(4) "do so, do that, do it" 用來代替動態動詞，而不能代靜態動詞。
Eg. — He gave up studying English.
— Why did he do so? (= give up studying English)
— The dish tastes nice.
— Yes, so it does. (tastes nice)
(此句不能用it does it 或 it does so, 因taste屬靜態動詞。）
(5) 為使語言精煉，避免不必要的重複，對話中常用省略形式。
E.g. — He is thinking of buying a car?
— Is he?（這裏，“thinking of buying a car”被省略了。）
— Will he come back in time?
— Perhaps.（省略了he will come back in time.)
