What do trees need? Why do we need trees? 求英语回答

What do trees need? Why do we need trees? 求英语回答 what do we need? Why do we need sleep Why do we need friend Why do we need soil? Why do we need friends? why do we need plants Do we need English literature?求回答（用英语）, The trees need+ do/doing还是to do? Why do you need friends? 用英语回答 why do we need a clean environment what we need和what do we need区别