我们必须拿起一些垃圾，扔到垃圾桶它。
21、As we know , water is very important to man.
我们知道，水是非常重要的人。
22、We can't live without water.
我们的生活离不开水。
23、We should not throw litter onto the ground.
我们不应该往地上扔垃圾。
24、Treat kindly the Earth is to treat kindly oneself.
善待地球就是善待自己。
25、Trees are very helpful and important for us.
树是非常有益的，对我们很重要。
