What’s the noise ? It sounds as if it comes from upstairs.   --______. It must be the window-cleaner working , next door.         

Some people are worrying about the possibility ________ mobile phones could be responsible for a range of illnesses, from rashes(皮疹) to brain tumors．

---It’s burning hot today, isn’t it?       ----Yes. ________ yesterday.

One more week,______we will leave school and have a holiday.

---You look unhappy, what’s happening, my son? ---I’m wondering how long it’ll be________ we come to China again.