---Why you are so worried? --- I ___for my little son all the afternoon, I don’t know why he hasn’t come back so late.
9.With the world changing fast, we have something new with all by ourselves every day.
10. Professor Williams keeps telling his students that the future to the well-educated.
The main cause of HIV / AIDS infection in China is drug abuse, ______ is very serious in Yunnan.
11.We should consider the students’ request the school library provide more books on popular science.
12. ---Hi, Tom. Any idea where Jane is? ---She in the classroom. I saw her there just now.