dinosaurs have been completely died out on the earth,never (being seen) again.

题目

dinosaurs have been completely died out on the earth,never (being seen) again.
为什么不可以直接用 seen
With a report ( to write )about the accident,I have to find some witnesses for help.
为什么不是 written
It's likely that he is the only American hip-hop artist ( to have ever lived) in China.
为什么不是 having ever lived、、、
About 3100 chinese citizens ( stuck ) in Thailand had returned by Dec.3rd.
having been stuck 的用法错在哪里~(>_

答案

1：如果我来做,我觉得seen也可以,但是我语感告诉我是being seen2：with 复合结构里,有两种形式,一种to do 一种done,考虑与report之间的关系,翻译得是将要写这个报道,所以才要找证人,事情还没有做也用to do的形式,如...