by the way 顺便说； 顺便问一下
Love to Bob, by the way.
请便代向鲍勃问好。
By the way, do you live with your parents or have a place of your own?
顺便问一句，你是同父母一起生活还是自己生活?

make fun of 开玩笑,捉弄
That will teach him a lesson! It doesn't pay to make fun of the Law, my man!
那会给他一个教训！与法律开玩笑绝不会有好下场，我的老弟。
Don't make fun of the poor boy.
不要取笑那个可怜的孩子。

at liberty 自由； 随意
I am afraid that I am not at liberty to discuss this matter.
对不起，我无权讨论这个问题。
You're at liberty to say what you like.
你尽可畅所欲言。