He was told he could join the army when he _____old enough.

He was told he could join the army when he _____old enough.
A、would be
B、should be
C、was
D、were
【正确答案】：C
【题目解析】：考查时态。主句是过去时，从句的时态通常要与主句一致。选项C是正确的。