It is the prevention of disease ________ its successful treatments that has led to the rapid increase of the world's population.

[　　]

---Did you visit the famous museum ?

　 ---No. We ______ it. But we spent too much time shopping.

　　A. can't have visited 　　　　　 B. could have visited

　　C. must have visited 　　　　　 D. shouldn't have visited

Your composition is good but your handwriting still requires　　　.

1. A.
   improving
2. B.
   improved
3. C.
   being improved
4. D.
   to improve

_____ his homework, he went out to play.

　　A. Having done 　　　　　　　　　　　　　B. Done

　　C. He has done 　　　　　　　　　　　　　D. He had done

We have eight foreign teachers in our school,five of _______ are young ladies.

A. them　　 B. whom

C. who    D. which