问题补充：
The boy insisted that he nothing wrong and that he at once.
A. did, should be set free
B. should do, must be set free
C. do, should be set free
D. did, must be set free
答案：
(答案→)A. did, should be set free
B. should do, must be set free
C. do, should be set free
D. did, must be set free
解析：考查insist的用法。Insist做坚持说解时从句与主句时态相同；做坚决要求...该...解时后接that+主语+should+动词原形；根据句意那个男孩坚持认为他没有错，并且坚决要求马上释放他。故选A。
