乱扔垃圾
1.throw litter about
2.drop litter
3.throw rubbish about
4.litter everywhere
不要乱扔垃圾
1.Don't litter
2.garbage here
别到处乱扔垃圾
保护环境
1.to protect the environment
2.environmental protection
3.protect the environment
4.Protection of Environment
如何保护环境
1.How to Protect the Environment