1. at (the) best至多，充其量，就最乐观的'一面来看。如：
Life is short at best. 生命再长也是短暂的。
At best a few hundred people attended the meeting. 充其量只有几百人参加了会议。
We can’t arrive before Friday at best. 我们无论如何也无法在星期五以前赶到。
2. do [try] one’s best 尽力， 竭尽全力。如：
As long as you do your best, we’ll be happy. 只要你尽力，我们就满意了。
It doesn’t matter if you don’t win---just try your best. 赢不了也没关系，只要努力即可。
注：其后有时可接不定式。如：
We did our best to help them. 我们尽力帮了他们。
3. had best 最好，应该。如：
You had best stay here. 你最好呆在这儿。
I think we had best sell it. 我想我们还是把它卖掉的好。
注：had best 与 had better 同义。
4. It’s best for sb to do sth 某人最好去做某事。如：
It’s best for us to start early. 我们最好早点出发。
It’s best for you to buy a dictionary. 你最好买台电脑。
5. make the best of 充分利用，尽量往好处做，将就用。如：
We must make the best of the fine weather. 我们必须要充分利用这好天气。
The only thing to do now is to make the best of things. 现在唯一的办法就是随遇而安。
