第1个回答 2011-03-23
What can trees be used for? 树能用来做什么?树有哪些用途?
第2个回答 2011-03-23
What's the function of trees?本回答被提问者采纳
第3个回答 2011-03-23
The reason why we have to grow trees is that they can supply fresh air for us.
我们必须种树的原因是它们能供应我们新鲜的空气。
第4个回答 2011-03-23
what is a tree used for?
第5个回答 2011-03-23
What's the use of trees?