思馬得英語100個(gè)句子學(xué)英語語法（51）：不定式的用法
<例句>
She didn't know whether to laugh or to cry.
她感覺真是啼笑皆非。
<語法分析>
不定式有時(shí)和連接代詞或副詞一起構(gòu)成賓語。在這個(gè)句子里，不定式就是這種用法。所謂不定式有兩種形式，即帶to的不定式和不帶to的不定式。不定式在多數(shù)情況下都帶to，不帶to的不定式和動(dòng)詞原形相同。不定式在句子里可以充當(dāng)很多成分，如充當(dāng)句子的謂語、主語、賓語、定于、狀語和表語等。它畢竟還是動(dòng)詞，因此具有動(dòng)詞的某些特征，如它可以有自己的賓語和狀語共同構(gòu)成不定式短語，它也可以有自己的邏輯主語。
<觸類旁通>
(1) Will you please call back again in a little while?
請過一會兒再打電話好嗎?
語法分析：不帶to的不定式和助動(dòng)詞共同構(gòu)成句子的謂語。
(2) She is said to have been to Canada many times.
據(jù)說她曾經(jīng)多次去過加拿大。
語法分析：不定式和某些被動(dòng)結(jié)構(gòu)在句子里構(gòu)成復(fù)合謂語。
(3) It is so good to talk to you.
和你談話真好。
語法分析：it作先行主語后面的不定式是真正的主語，這樣可以使主語避免顯得過長，常見的這類句子結(jié)構(gòu)有it+be+形容詞+不定式， it+名詞或動(dòng)詞+不定式以及it+be+介詞短語+不定式等。
(4) I asked her to convey my best wishes to her mother.
我請她向她的母親問好。
語法分析：“名詞或代詞+不定式”的形式跟在動(dòng)詞后面可以在句子中做復(fù)合賓語，這樣的動(dòng)詞有很多。
(5) Did you see anyone enter the office?
你看見什么人進(jìn)辦公室了嗎?
語法分析：在諸如see, hear, let, watch, notice, have, fell等某些動(dòng)詞后面可以跟不帶to的不定式，構(gòu)成句子的復(fù)合賓語。
(6) She's a nice person, to be sure.
可以肯定，她是個(gè)好人。
語法分析：不定式修飾整個(gè)句子，因而稱之為句子狀語。
<鞏固練習(xí)>
1. She likes to half _____[close] his eyes.
2. I told him to stay at home and _____[wait] till I came back.
3. She was sent abroad _____[educate].
4. The baby seemed _____[dream].
5. She was known _____[work] for the International Olympic Committee.
6. Would you like something _____[drink]?
7. It isn't right _____[waste] so much money on it.
<參考答案>
1. close 2. wait 3. to be educated 4. to be dreaming 5. to have worked 6. to drink 7. to waste
