Only when the war was over return home.
A. he was able to
B. was he able to
C. could he be able to
D. would he be able
网友回答
A. he was able to
(答案→)B. was he able to
C. could he be able to
D. would he be able
解析：考查倒装结构。本题考查Only + 状语从句 + 主谓倒装结构，be able to用其过去式，表示成功的做某事，故选B。