单选题：________your help, how could I have passed the difficult int..

I always take something to read when I go to the doctor's ________ I have to wait. [ ]A. in caseB. so thatC. in orderD. as if

— I'm really confused on how to balance my interest and study. — Well, turn to your teacher for advice, in my opinion, _____ you'll make it. [ ]A. but B. andC. soD. unless

___ he made up his mind, nothing could change it. [ ]A. BeforeB. Unless C. When D. Once

—Did you catch the early bus this morning?—No.It had left the stop _____ I arrived there.[ ]A. as soon asB. as the timeC. by the timeD. during the time

She had just finished her homework _____her mother asked her to practice playing the piano yesterday. [ ]A. when B. while C. after D. since