# Ex.3
1) You usually go there by train. Why not ______by boat for a change this time?
A. to try going
B. trying to go
C. to try and go
D. try going
2) Paul doesn't have to be made ______. He always works hard.
A. learn
B. to learn
C. learned
D. learning
3）The chair looks rather hard, but in fact it is very comfortable to ______.
A. sit
B. sit on
C. be seat
D. be sat on
4）I find German language hard______.
A. learned
B. learning
C. to learn
D. to be learn
5) I ran too fast ______where I was going.
A. to notice
B. and notice
C. of me to notice
D. noticing
6) He went to a bookstore______some magazine.
A. buy
B. for buy
C. to buy
D. buying
7) Paul does nothing but _____all day long.
A. play
B. to play
C. playing
D.played
8) I saw mary open the door and ______.
A. to go into
B. got into
C. get in to
D. getting into
9） Mr.Smith was seen______the museum.
A. enter
B. to enter
C. to entering
D. to have entered
10）It ______ me three days to finish the task
A. cost
B. took
C. spent
D. used
A:
1) D ; 解析：存在why not需要省略to，一般跟上动词的ing形式
2）B； 解析：存在have，但是被动语态所以不省略to
3) B; 解析：根据不定式的复合结构 It's + 形容词 + to do sth.
4) C; 解析： to do sth
5) A; 解析： ...too...to...固定搭配
6) C; 解析：为了表示目的使用不定式 to do sth...
7) A; 解析：当两个或多个不定式短语由连词and, but 或or 连接时，后一个或几个不定式符号to 常省略
8) C;解析：感官动词，省略to，并且和前面的“open”成对比
9) B; 解析：感官动词，被动语态，需要恢复to
10) B; 解析： cost 只能用于钱，took(take的过去式）