9.look down upon Bob. He has his own advantages.

　　Oh， yes. ________ others are weak， he is strong.

　　A. If B. When C. Where D. Though

　　10.The day must be breaking， _____ the birds have begun singing.

　　A. because B. as C. for D. since

　　11.John may phone tonight. I don’t want to go out ________ he phones.

　　A. as long as B. in order to C. in case D. so that

　　12.____others say， the expert is sure that his theory is correct

　　A. No matter B. It doesn’t matter C. Whatever D. What

　　13.Many places are flooded by heavy rainfalls， so they can’t walk _______ they like these days.

　　A. when B. whenever C. where D. wherever

　　14.His father began to work ______ his childhood.

　　A. since B. before C. as early as D. while

　　15.The roof fell _____ he had time to dash into the room to save his baby.

　　A. before B. as C. after D. until