159.I knocked over my coffee cup.It went right over ____ keyboard.

You shouldn't put drinks near ____ computer.

A.the;/

B.the;a

C.a;/

D.a;a

160.Of all ____ reasons for my decision to become a university pfofessor,my father's advice was ___ most important one.

A.the;a

B./;a

C./;the

D.the;the

159.答案是B，

第一空特指；第二空泛指。

160.答案是D，

of all后面习惯上接定冠词the；第二空为形容词的最高级，所以必须用定冠词the。