Charles Babbage is generally considered______the first computer.
A. to invent       B. inventing     C. to have invented   D. having invented

 The computer centre,______last year, is very popular among the students in this school.
A. open     B. opening      C.having opened      D. opened

 "Can't you read?"Mary said_____to the notice.
A. angrily pointing         B. and point angrily
C. angrily pointed          D. an angrily pointing

 _____is a good form of exercise for both young and old.
A. The walk     B. Walking     C. To walk     D. Walk

 I would appreciate______back this afternoon.
A. you to call      B. you call      C. your calling     D. you're calling

——I usually go there by train.

——Why not____by boat for a change?
A. to try going 　 B. trying to go 　 C. to try and go D. try going

 Little Jim should love_____to the theatre this evening.
A. to be taken     B. to take     C. being taken      D. taking

 The salesman scolded the girl caught______and let her off.
A. to have stolen        B. to be stealing    C. to steal             D. stealing

 ____a reply, he decided to write again.
A. Not receiving         B. Receiving not
C. Not having received    D. Having not received

——Shall we go skating or stay at home?

——Which____do yourself?
A. do you rather 　 B. would you rather
C. will you rather 　 D. should you rather