Susan decided not to work on the program at home because she didn’t want her mother to kno

问题补充：

Susan decided not to work on the program at home because she didn’t want her mother to know what she .

A. has done

B. had done

C. was doing

D. is doing

答案：

A. has done

B. had done

(答案→)C. was doing

D. is doing

解析：考查时态：句意：Susan决定不在家里从事这个工作，因为她不想她的妈妈知道她做得事情。说明是过去正在做的事情。选C。