Question

There was __________ time when the two countries were at __________ war.

A．the; /

B．the; the

C．a; /

D．a; a

Answer 1

C

a time指“一段时间”，为泛指；be at war为固定搭配，表示“处于战争状态”，这里的冠词均为约定俗成的用法。