1.He couldn't help crying when he heard the sad news.(can't help doing sth 忍不住.)
2.The more carefully you work ,the fewer mistake you will make.(the比较级...the比较级越.越.)
3.After you use the plastic bags you mustn't throw them about.(throw sth about 乱扔.)
4.We must protect the trees from fire.(protect sth from 保护.避免)
5.He ran out of gas a mile from home.(run out of 用光了,用完了)
6.I think students are supposed to wear school uniforms at school.(be supposed to 应该,认为必须,被期望)
7.Parents should stop their children from telling lies.(stop sb from doing sth阻止.)
8.I happened to meet my aunt.(happen to碰巧 )
9.He was tired of doing the same work every day.(be tired of厌烦、、、)