Dinosaurs have been extinct from the earth,never__again A.seen B.being seen C.to be seenD.having been seen为什么选C

Turtles and tortoises have been on planet Earth even before the dinosaurs.是什么意思 sharks are amazing fish that have been around since long before the dinosaurs existed翻译并分析句子结构 Dinosaurs have been extinct from the earth,never__again A.seen B.being seen C.to be seenD.having been seen为什么选C They are that old.怎么翻译?Turtles and tortoises have been on planet Earth even before the dinosaurs.They are that old. appear to have been的用法1.the dinosaurs appear to have been relatively smart2.the Neanderthals appear to have been equipped to face any obstacle the environment could put in their pathdinosaurs 和 neanderthal(智人)都是过去的事情,为什 ______years ago ,very large animals called dinosaurs _______lived in sone areas of the world.A.Many millio;have been living B.Million;had livedC.Several millions of;are alive D.Millions of;lived还有翻译是什么? Turtles and tortoises have been on planet Earth even before the dinosaurs.turtles海龟tortoise龟planet行星dinosaur恐龙希望英语好的人帮帮我翻译一下这个句子! have been have been have been have been 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 dinosaurs 快 Dinosaurs是什么意思? have been还是have been being? have since been 和 have been since have been 和have ever been区别! have broken have been broken?