He ______ be at home, because the light in his room is on.

A: _________ do you exercise? B: I exercise every day!

We’re going to Suzhou Amusement Park in Linda's card. You can come with us______you can meet us there later．

 -- _____ classes are there in your school?   –Thirty. 

—— Hurry up. The bus is coming! —— Oh, no, we mustn’t cross the street ______ the traffic lights are green.