问几个英语的语法问题She said she (was) flying to Shanghai next weekend

问几个英语的语法问题
She said she (was) flying to Shanghai next weekend.（这里为什么是填was而不是will be）
The ship was full of people.There was no (rooms) for Elen.（这里的room为什么是复数）
If you want to talk to your teacher,you should（called to her）first.（这里为什么是“called to her”而不是“call her up”）
In ten years,John (was) an astronaut.（这里为什么是was,而不是will be）