Cat got your tongue?
你的舌头打结了吗?

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这句话通常是用问句的方式问对方, 就像例句写的一样, Cat got your tongue? 记得我刚来美国不久, 每次要讲英语不是舌头打结就是脑袋瓜打结. 有一次老美问我 How are you doing? 结果我一方面想回答 good! 一方面又想成 not much. 结果就结结巴巴说成了 not good. 那个老美就对我投以同情的眼光说, Cat got your tongue?

总之对方说话说的不清不楚, 或是你听不懂对方在说些什么, 你就可以开玩笑地说 , Cat got your tongue?

Don't be shy .  Cat   got your tongue???  ,I can't get what you say.[s:12]

there are many meanings about "get"
a )理解，明白，懂得
He just didn't get it.
他就是不明白那笑话。
Oh,the paper's supposed to go in the way up.i get it.
啊，这纸得这面朝上放进去，我们不了。

b)you've got me there.
你把我难倒了。

c)报复
I'm going to get you for that.
我要为那事找你报复！

d)Get on with it!快一点！
will you lot stop messing around and get on with it.
你们别再瞎胡闹了，快点干好不好好！

e)Get on/along with you!
别胡扯！

f)Cat got your tongue? 你的舌头打结了吗?

has the cat got your tongue?

Cat got your tongue? I do not. I'm just a little bit shy!

Cat get your tongue.

Nothing in the world is difficult for one who sets his mind to it.
I'm just a little bit shy.
I'm shy

Cat got you tongue.

Cat got your tongue?
No,I'm a little bit shy.

Cat got your tongue