Unit 4 Wildlife Protection
单句语法填空
1．More attention should be paid to (improve) the safety of school buses, which has become a big concern of the whole society.
答案：improving
2．Around 540 million people hand smoke, which causes 100, 000 deaths per year.(affect) by second
答案：are affected
3．I received a letter (contain) some important information about the project.
答案：containing
4．I got close enough to hear them speaking Chinese, and I said “Ni Hao”， just I might do in China.
答案：as
5．So I suggest you (keep) the balance between your study and entertainment, such as doing sports, listening to music and so on.
答案：(should) keep
6．We appreciate (participate) in this activity, which has helped to build an emotional connection between the old and the young.
答案：participating
