trybesttodo还是doing

是try best to do，例如：

1、Now that the decision has been made， we must try our best to carry it out.既然已经作出了决定，我们就必须尽自己最大的努力去执行。

2、I'll try my best to free them from doubts and misgivings.我要尽力消除他们心中的疑虑。

3、You should try your best to avoid making mistakes while taking an important exam.你应该尽量避免在参加重要考试时出错。