I've twisted my ankle.

我的脚踝扭伤了。

A: What's up? Why are you limping?

A: 怎么了？你为什么一瘸一拐的？

B: I twisted my ankle. It really hurts.

B: 我的脚踝扭伤了，很疼。

A: How did you do that?

A: 怎么搞的？

B: It was nothing serious. I just twisted it when I was walking.

B: 没什么大事，是我走路的时候扭伤的。

A: It looks swollen. You shouldn't walk on it. You should rest.

A: 看起来肿了。你不应该再用伤脚走路了，应该休息。

B: I know. I'm going to put some ice on it.

B: 我知道，我打算在上面敷些冰。

Notes:

1. 要问某人发生了什么事，你可以说：What's up? 或者 What happened?（怎么了？）

2. 当你扭伤脚踝时通常可以说：I twisted my ankle. 或者 I sprained my ankle.（我扭伤了脚踝。）

下面再来补充几个表示“扭伤”的单词：

sprain
vt. - to injure or impair by overuse or overexertion 因使用过度或过量施加而受伤或受损；拧伤；扭伤，扭坏关节
n.扭伤；扭筋
例：to sprain one's wrist 扭伤了手腕
He got a severe sprain in his ankle. 他脚踝受了严重的扭伤。

wrick
vt. 扭伤，轻微扭伤（颈、脊骨等）
n. 扭伤，扭筋
例：give sb.'s back a wrick 扭伤某人背脊

wrench
vt. - to twist and sprain 扭伤，扭曲并拉伤
n. 扭伤
例：to wrench sb.'s back 扭伤某人的背
I wrenched my knee. 我扭伤了膝盖。
He gave a wrench to his ankle when he jumped down. 他跳下去的时候扭伤了足踝。

strain
vt.（身体的）扭伤，拉伤
例：to strain a muscle. 扭伤肌肉
I strained my back when I lifted the box. 我抬箱子的时候扭了背。
Don't strain yourself! 不要劳累过度！