I can(not) imagine that they could (not) finish it in such a short time上面句子中的not 应该放在can后面还是could后面为什么?

I can(not) imagine that they could (not) finish it in such a short time上面句子中的not 应该放在can后面还是could后面为什么?
I can(not) imagine that they could (not) finish it in such a short time
上面句子中的not 应该放在can后面还是could后面为什么?

I can(not) imagine that they could (not) finish it in such a short time上面句子中的not 应该放在can后面还是could后面为什么?
oberviously,the word "not" should be insert the back of imagine!
这种从句很常见!

你想表达什么意思?放在can后面表示我不能想象他们在如此短的时间内就完成了,而放在could后面表示我可以想象他们不能在如此短的时间内完成.