My father began to work ____ a bus driver when he was twenty years old.
| A．for | B．to | C．at | D．as |
44. Please tell me ______ you would like to have your coffee --- black or white?
| A．how | B．what | C．when | D．Which |
43. ______ he was absent, I was expected to take his place greatly surprised me, for I didn’t have much experience.
| A．If | B．If that | C．That if | D．That |
42. You’d better start it right away ______ you forget it.
| A．in case of | B．unless | C．before | D．Since |
41. If it ______ for the fence, he ______ into the river.
A. were not; fallenB. had not been; could have fallen
C were not; could fall D. had not been; could fall
40. I could have offered you some help last weekend, but I ______ with my work at that time.
| A．would be occupied | B．was occupying | C．had been occupied | D．was occupied |