do, doing還是to do

請(qǐng)看這樣一道題：

Everyone in our class was working hard and doing what we could _______ a good college.

A. enter B. to enter

C. entering D. entered

【陷阱】容易誤選A。有的同學(xué)一看到空格前的情態(tài)動(dòng)詞 could 就斷定此處應(yīng)填動(dòng)詞原形 enter。

【分析】其實(shí)正確答案應(yīng)是B。此句為省略句，即在 could 后省略了動(dòng)詞 do，若把句子補(bǔ)完整應(yīng)為Everyone in our class was working hard and doing what we could do to enter a good college。即句中的不定式短語(yǔ)(to enter a good college)是用作目的狀語(yǔ)的，而不是與情態(tài)動(dòng)詞(could)一起構(gòu)成謂語(yǔ)。請(qǐng)?jiān)倏搭愃评洌?o:p>

(1) They did what they could to comfort her. 他們盡量安慰她(from www.網(wǎng)址未加載)。

(2) They did everything they could to save her life. 他們盡一切力量拯救她的性命。

(3) He studies as hard as he could to catch up with his classmates. 他拼命學(xué)習(xí)以便趕上他的同學(xué)。

值得指出的是，這也并不是說(shuō)今后只要遇到類似結(jié)構(gòu)的題就一定選帶to不定式。請(qǐng)看以下試題：

(4) He ran as fast as he could _____ to catch the early bus.

A. to hope B. hope

C. hoping D. hoped

此題的答案是 C不是A，其中的現(xiàn)在分詞短語(yǔ) hoping to catch the early bus 用作伴隨狀語(yǔ)。

(5) He spent every minute he could _____ spoken English.

A. practise B. to practise

C. practising D. practised

此題答案選 C，這與前面動(dòng)詞 spent 的搭配有關(guān)，即 spend … (in) doing sth。若將此句補(bǔ)充完整，即為 He spent every minute he could spend in practising spoken English.

(6) Before going abroad he devoted all he could _______ his oral English.

A. improve B. to improve

C. improving D. to improving

此題答案選D，注意兩點(diǎn)：一是 devote … to … 是固定搭配，意為“把……貢獻(xiàn)給……”；二是其中的 to 是介詞，不是不定式符號(hào)，后接動(dòng)詞時(shí)要用動(dòng)名詞(from www.網(wǎng)址未加載)。