这句话里能不能把should后面的be变成is为什么?likely to 后面为什么要加be??而不是by或者is?
The agents of other firms should be able to trace the kind of resertch they are likely to be undertaking. 这句话里能不能把should后面的be变成is为什么?likely to 后面为什么要加be??而不是by或者is?
补充: 情态动词还包括 must can could may might dare等等 to 有时候是介词 此时后面的动词要加Ing
例句: Li Ming's mother says "you must finish your homework right now"to his son.李明的妈妈对儿子说:"你必须现在就把作业做完"。 i will look forward to hearing from you soon. 我期待很快收到您的回复。