各位老师好，从一本练习册中看到一个阅读问答题，文章是这样：

The environmental problems are more and more serious. We must do our best to protect the environment.

There are many different ways to save the environment.

Plant more trees. Choose a right ground near your house or workplace. If there aren't any rules to stop you from growing trees, plant more trees.

You can invite (邀请) your friends and families to join you.

问题是这样的：

Where can you plant trees according to the text?

______________________________________________.

答案给的是：On a right ground near your house or workplace.

我有两个疑问：

1. 种树为什么用on a ground而不用in a ground, 种的树不能都在地表面上，而是有一部分在地里，我认为用in the ground更好吧？

2. 问题中问can you...，那么在回答时不需要把第二人称变成第一人称吗？

我的答案是: In a right ground near my house or workplace.

请各位老师指教，谢谢！