重点讲解：
1. try doing sth.
尝试做某事；
eg. You can try swimming in winter to keep healthy.
你可以试着在冬天游泳来保持健康。
eg. If you're having trouble deciding when to hold on to something and when to let it go, try doing things backward.
如果你在烦恼什么时候去拥有一些东西和什么时候放手，试着考虑做事情的结果。
2. at once
同时；一起；
eg. You can't be doing two things at once.
不能一心二用。
eg. No bank could ever pay off its creditors if they all demanded their money at once.
如果所有的储户同时要求提取存款，没有哪家银行能办得到。
3. save time
节省时间；
eg. In the United States, many people try to save time.
在美国，许多人都尽量节省时间。
eg. We can save time if we go this way.
如果我们走这条路，就可节省时间。