try可以做名词，也可以做动词。

一、try做动词时

1、try to do sth. 努力做某事（强调付出一定的努力了）
The little boy tried to reach the apple on the table.
这个小男孩尽力去够桌子上的苹果。

2、try doing sth. 尝试做某事（不一定付出努力了）
Jack isn't here. Try phoning his home number.
杰克不在这儿。给他家里打电话试试。

3、try on 试穿 
I tried on a new coat yesterday,but it did not fit me well.
我昨天试穿了一件外套，发现它根本不适合我。

4、try/do one's best to do sth.  尽某人最大努力做某事 
I will try my best to help you.
我会尽全力帮助你。

二、try做名词时
have a try 试一试 

He would like to have a try at / for this chance. 
他将愿意试试这次机会。

Let me have a try at / for it.
让我试一下。