My father served in the army in when he was in .A. 1950s; twentiesB. the 1950s; his twenti

问题补充：

My father served in the army in when he was in .

A. 1950s; twenties

B. the 1950s; his twenties

C. the 1950s; the twenties

D. 1950s; the twenties

答案：

A. 1950s; twenties

(答案→)B. the 1950s; his twenties

C. the 1950s; the twenties

D. 1950s; the twenties

解析：考查短语。in the 1950s 在20世纪50年代，这是固定的表达。In one’s twenties 在某人20多岁的时候。选B。