I insisted that the boy his hands before having supper.A. washesB. washedC. had washedD. (

问题补充：

I insisted that the boy his hands before having supper.

A. washes

B. washed

C. had washed

D. (should) wash

答案：

A. washes

B. washed

C. had washed

(答案→)D. (should) wash

解析：考查动词insist坚持要求，后跟从句用(should )do ,j句意：我坚持要求这个男孩应该吃饭之前洗手。所以选D。