That tree, __________ branches are almost bare, is very old.

A. whose 　　　 B. of which 　　　 C. in which 　　 D. on which

－－The button in the kitchen is out of order.

－－_______.

A.    I’m really sorry to hear that.　　 B. No problem. It’ll be OK.

　 C. Anything else I can do?　　 D. Why not get Mr. Kidder to have a look

________ is it that metals play such an important part in our daily life?

A. Why　 B. What　 C. Where　 D. When

I’m __________ (极其) sorry to have kept you waiting for so long a time.

___ the fact that his initial experiments had failed, Pro. White persisted  (坚持) in his research. 
A. Because of      B. As to      C. In spite of     D. In views of 

The injured person lay on the ground, b_____________heavily.

Edison kept phosphorus carefully in a bottle lest it ___.
A. would burn 　 B. burned 　　　 C. was burning 　　 D. should burn

There are 800 students in our school, _____are girls.

A. 50% of then　　　 B. 50% of which

C. 50% of whom　　 D. 50% of the students

The flowers his friend gave him will die unless ________ every day.

　 A. watered　　　　　 B. watering　　　　　 C. water　　　　　　　　 D. to water

No one had told Smith about ______ a lecture the following day.

　　　　　　 　 A. there be　　　 B. there being　　 C. there would be　　 D. there was