__ does he call? Once a month
1. ________ does he call? Once a month.
A.How seldom
B.How long
C.How soon
D.How often
.标准答案：D
2. Looking through the window, I found him ________ in a sofa.
A.to seat
B.seat
C.seating
D.seated
.标准答案：D
3. I told your friend how to get to the hotel, but perhaps I _________ have driven her there.
A.could
B.must
C.ought
D.should
.标准答案：D
4. You should be careful when __________the street in big cities.
A.to cross
B.cross
C.crossing
D.crossed
.标准答案：C
5. An invention is usually the end result of a long ___ of ideas, expressions, and improvements.
A.selection
B.sequence
C.combination
D.cooperation
.标准答案：B
