啊，对啦!
That's it! *正中对方话语、行为的核心，惊讶或高兴时用。
Let's push this button. (摁这个按钮看看。)
That's it! (啊，对啦!)
Let's try this way. (用这个方法试一试。)
That's it! (啊，对啦!)
That's a winner.
Sounds like a winner.
That's not it. (啊，不对。)

正是!
You got it. *直译是“我说的话你正确地理解了”。
Do you mean this one? (你的意思是这个?)
You got it. (正是!)
You've got it.
That's right.
You know it.

你说到点子上了。
Your answer is to the point. *Your answer is very to the point. 加上very后，句中就含有“确实掌握了要点”的语感。
We should fire him. (我们应该解雇他。)
Your answer is to the point. (你说到点子上了。)
That's a very straightforward¹ answer.

应该是吧。
I bet.
It's true. (这是真的。)
I bet. (应该是的。)
①那好吧，拜托您了!/那谢谢了。
②为什么不行?
Why not? *Why not? 有两种意思：
(1)accepting (接受承诺)在别人的建议下回答“麻烦您……”，作“谢谢。”时使用。
(2) questioning (询问理由)是询问“为什么不行?”的。
1) Would you like some more? (您还想再要点儿吗?)
Why not? (好的。)
No reason not to.
Sure.
Thanks.
No problem.
2) You can't see your friends today. (今天你不能去见你的朋友。)
Why not? (为什么不行?) 
 
对啰!
Bingo! *俚语。表达类似“说对了!”、“猜中了!”的意想不到的喜悦心情。
You play tennis, right? (你打网球是不是?)
Bingo! (对呀!你说对了。)
说得对!说得好!
Hear, hear! *对演讲人说出的重大的事情表示充分赞成的表达方式。
We should lower taxes! (应该减少税金。)
Hear, hear! (说得对!说得对!)

是，先生/女士。
Yes, sir. *对男性。
Yes, ma'am. *对女性。
I'd like a wake-up call, please. (请提供叫早服务。)
Yes, sir. (是，先生。)
No, sir./No, ma'am. (不，不对。) *用于工作中的有礼貌的说法。