1、一篇短文填空：When she returned,and the coffee and sandwiches had

1、一篇短文填空：When she returned,and the coffee and sandwiches had ______.(go)
我选了been gone..因为我看到一本练习册里说be gone =be missing =be lost表“不见了的,失去的”.
但是答案是gone.有谁能告诉我be gone与have gone的区别啊?
2、The man became more and more puzzled.At last he said,"Excuse me ,but _____ you read at all?"
答案是can...但我想at all 不是与not 连用的吗,我就选了can't.
请问at all 也可以用於肯定句的吗?
3、somewhere是不是相当于地点副词here there home这样的用法：前面不用介词啊?、
如接move to...这样的词时,需要加to吗?
4、看到一些书上表示在地球上好像on earth 与on the earth都用这样用,请问它们有区别吗?（当表示“在地球上”的意思时）
5、human与human being表人类时一般要加s.那么用复数对吧？
man表人类时，前面用不用定冠词the?