I feel exhausted¹.

我感觉筋疲力尽。

A: You look tired.  It's been a long day.

A: 你看起来疲惫。你忙了一整天。

B: Yes, it has.  I'm exhausted.  I'm so tired.

B: 是的，是这样。我筋疲力尽了。我太累了。

A: Well, I'm not surprised.  We've done a lot today.  Lots of walking.

A: 哦，我不惊讶。我们今天做了很多事情。走了太多的路。

B: I know.  I'm so tired that I could fall asleep right now.

B: 我知道。我太累了，以至于马上就能睡着。

A: Well, why don't you go and have a rest?

A: 哦，那你为什么不去休息一会?

B: You're right.  A good, long sleep. That's what I need.

B: 你说得对。好好地睡一大觉。这正是我所需要的。

Notes 注释

1. You can say to people directly: You look tired. / You look tired; or You look good. / You look good.
你可以直接跟某人说：You look tired. / 你看起来很疲惫;或者 You look good. / 你看起来气色很好。

2. You can also suggest things to people by saying: Why don't you . . .? / Why don't you . . .? e.g. Why don't you have a rest? / Why don't you have a rest?; Why don't you take an aspirin²? / Why don't you take an aspirin?
你还可以这样给某人提出建议；Why don't you . . .? / 你为什么不 . . .? 例如: Why don't you have a rest? /你为什么不休息一下呢？; Why don't you take an aspirin? / 你为什么不吃一片阿司匹林呢？

3. Remember you can use so/so to emphasise³ something, e.g. I'm so tired I could fall asleep. / I'm so tired I could fall asleep.
记住你可以用so/太来强调某事，例如：I'm so tired I could fall asleep. / 我太累了，以至于马上就能睡着