My father began to work a bus driver when he was 20 years old.A. forB. toC. atD. as

问题补充：

My father began to work a bus driver when he was 20 years old.

A. for

B. to

C. at

D. as

答案：

A. for

B. to

C. at

(答案→)D. as

解析：考查介词：A for为了，B. to给…到…，C. at在…地点，D. as做为，work as“担当”，句意：我爸爸20岁的时候，开始做公共汽车司机的工作。选D。