3．Protons(质子) are nearly________________(2 000 倍重) as electrons.

　　4．At present，________________(......的数量) young people who smoke is________________(正在增加)．

　　5．There is a chance that he may fail in the exam，because he is too careless.(同义句)

　　________________that he may fail in the exam，because he is too careless.

　　6．____________________(我是外国人这事实)was a big disadvantage.

　　7．____________________(众所周知)，China is a developing country.

　　8．It was said that imported steel________________(比有优势) steel made at home.

　　9．He added that the film should win________________(它被提名的所有奖项)．

　　10．He and his friends like going shopping.(同义句)

　　He________________his friends likes going shopping.

　　答案

1．not until；that　2.guarantee to study hard 3．2，000 times as heavy 4．the number of；on the increase 5．The chances are　6.The fact that I was a foreigner 7．As is known to all/we all know 8．had