高考英语：Her relatives are all here and his---come yet. ---seems

问题提得好!
第一句之所以要用haven't,是因为his后面省了relatives（复数）,是比较刁钻的题.
第二句应该是很容易的.为便于理解,可将该句简化成there was no need to wait,指过去的等待,而不是今后.如果说It was no need to wait,当然就不行了.如在seem前坚持要用It,只能在当中加主语,将句子改成从句：It seems we had no need to wait.
既然不加主语,当然就只能保持there is no need这种句型.
但加了seems之后,原来过去时的was就只能改成不定式里的完成时to have been了.所以,就的写成There seems to have been no need to wait.