We all suggested the plan ________, but the boss insisted that his plan ________ perfect．

A.put off; was

B.should put off; is

C.be put off; was

D.should be put off; is

答案及解析： C

解析：

suggest(建议)后面接虚拟从句(should be done)；

insist在这里是：坚持认为。后面的从句是真实的叙述，其时态与主句时态范围一致。