I think （that） you will like this school soon.
You should decide （whether） you go there by air or by train.
There are two apples on the desk,but she doesn`t know （which） is sweeter.
The teacher wants to know （whether） Tom will go to school or not tomorrow.
He asked me （if） I could help him.
It is hard to say.Nobody knows （whose） mistake it is.
——Please tell me （when） we will have the meeting.——At 3 p.m.