The Internet celebrated its birthday on September 2nd, by which time 40 years _______ since the first successful transfer of data between two computers.

一Tom，you’ve got an A in the final English exam．Congratulations!
一Thanks．But I never thought the result came out so fast．The papers     when I left the
Teacher’s office just now．  

---Where _______ my book ? I can't see it anywhere. 
--- I _______ it on this table . But now it's gone .
A were you putting ; have put           B. had you put ; was putting 
C have you put ; put                     D. did you put ; have put 

Mr. Smith found that gas         from the pipe when he came back because we forgot to switch off. But at last we were lucky to escape           .

-----The windows must have taken you quite a long time that day.
------Right. They          for weeks.

I ______ him in time, otherwise he would have fallen off the bike.

I can’t see any sugar in this cupboard.            ?

My son __________ his clock  when I went to get a cup I __________ in his study.

All those _____ about the poor children should be _____.

In order to stop poverty, the World Bank has ______ its focus to providing technical assistance and long-term loans to developing countries.