— Hello, Betty! Where are you now?  — I ________ on the Great Wall of China and talking to you.        

Since we ________ our homework now. Let’s have a rest. 

 Tom ________ a letter from Terry for a long time.

Beijing ______a lot in the past ten years. Now it has become one of the biggest modern______ in the world. 

 ---I don’t know what _____ if I do that. ---I think you ______ tell him the whole thing first.