If there hadn’t been so much smog in Beijing, we______________ the beautiful scenery across the Tiananmen Square.

—I knocked but nobody answered the door. ----They _____asleep then and didn’t hear you.

There       be any difficulty about passing the road test since you have practised a lot in the driving school.

 Mr Li required the computer equipment referred ________ used in every classroom. 

—Is the letter from your mother?—Yes. But she ________ the letter herself, because she doesn't even know one word.