The main cause of HIV / AIDS infection in China is drug abuse, ______ is very serious in Yunnan.
— Have you seen the film Under the Hawhorn Tree? —Of course, I have. It was in our village _____ it was made.
You can see the stars on a clear night, but in the daytime they are _____
I_______ such a foolish mistake if I had been a little more careful.
Look over there—there’s a very long, winding path _____ up to the house.
I was out of town at the time, so I don’t know exactly how it _______.