動詞不定式與動詞-ing形式
動詞不定式和動詞-ing形式不能單獨作謂語，在使用時分別有下面幾點需要注意：
（一） 動詞不定式
1．feel, hear, listen to 等感觀動詞和 have, let , make等使役動詞后的補足語，在主動語態(tài)中，不定式不帶to；在被動語態(tài)中，則必須帶to。如：
I often hear him sing the song. / He is often heard to sing the song.
2. 不定式短語位于介詞but, except, besides后時，如果這些介詞之前有行為動詞do 的各種形式，那么，這些介詞后的不定式不帶to，否則要帶to。如：
She could do nothing but cry. / It has no choice but to lie down and sleep.
3. 不定式修飾的名詞或代詞與不定式邏輯上構(gòu)成主謂關系時，不定式往往用主動形式。如：
Have you got a key to unlock the door? (A key unlocks the door.)
4. 不定式和它前面被修飾的名詞或代詞構(gòu)成邏輯上的動賓關系，又和該句的主語構(gòu)成邏輯上的主謂關系時，不定式常用主動形式。如：
I have got a letter to write.( I write a letter.)
5.如果不定式作表語形容詞的狀語，且和句中主語構(gòu)成邏輯上的動賓關系時，不定式多用主動形式。如：
The book is difficult to understand.( to understand the book)
（二） 動詞 -ing形式
1． 不定式和動詞 -ing形式都可以做主語，動詞 -ing形式做主語表示一般或抽象的多次性行為；不定式做主語往往表示具體的或一次性的動作。如：
Playing with fire is dangerous.（泛指玩火) / To play with fire will be dangerous.（指一具體動作）
2． admit, appreciate, avoid, consider等動詞后一般用動詞 -ing形式做賓語。
3． 在allow, advise, forbid, permit等動詞后直接跟動詞作賓語時，要用動名詞形式；如果其后有名詞或代詞做賓語，然后再跟動詞作賓語補足語時，其賓語補足語用帶to的不定式。如：
We don't allow smoking here. / We don't allow students to smoke.
從下面每題所給的四個選項（A、B、C和D）中，選出最佳選項。
1. Every detail should be thought of ______ that nothing bad will happen during the Olympics.
A. make sure B. to make sure
C. making sure D. be made sure
2. I think ______ at the Net-bar will surprise Aunt Kate.
A. your being B. you are
C. you being D. you to be
3. —Did that book give the information you need?
—Yes, but ______, I have to read it entirely.
A. for finding it B. to find it
C. finding D. finding it
4. — Did you enjoy your visit there?
— Yes, but I'm very sorry ______ so soon.
A. for leaving B. of leaving
C. to leave D. to have left
5. The professor spoke slowly enough to make his speech easy ______.
A. follow B. to follow
C. followed D. following
6. — I thought you had planned to practise the piano today.
— No. I did nothing but ______ computer games all day.
A. play B. to play
C. played D. playing
7. It is I, ______, that ______ blame for the fault.
A. not him; is to B. not he; is
C. not he; am to D. not him; are to
8. It is important for parents and young people to learn how to get through to each other and develop skills in understanding and ______ understood.
A. being B. be C. are D. to be
9. We still have many difficulties ______ in our socialist construction.
A. to overcome B. to be overcome
C. overcome D. to have overcome
10. The lost child desired nothing but ______ home to see his parents.
A. go B. to go C. going D. went
11. He was lucky enough ______ when he cheated in the exam.
A. not to be seen
B. to not have been seen
C. not to have been seen
D. to not be seen
12. Mrs Harley has a habit of asking questions ______.
A. but then not listen to the answers
B. and then not listen to the answers
C. but then not listening to the answers
D. and then doesn't listen to the answers
Keys： 1-6 BABDBA 7-12 CAABCC