crack a joke;joke;make fun of;play a trick;badinage ;
例句:
Their behaviour is an offence. It's no laughing matter.
他们这么做是犯罪,这可不是开玩笑的.
John smiled at them and gave Richard a playful poke.
约翰冲着他们笑了笑,开玩笑地捅了理查德一下。
I'm serious, things are difficult enough as they are.
我可不是开玩笑,事情够麻烦的了.