I'm tired.
不管是在原因中还是最新的一个话题中，都有对累的描述，我们需要积累不同的表达方式，这样才可以避免重复。
当然，还需要注意好用法额～

加副词来表示程度
I'm very tired.
I'm kind of tired.
He is pretty tired.
I am unbelievably tired.
She is mentally tired.
We are physically tired.
I'm dead tired.
I’m dog-tired.
I’m tired to the bone.

I'm exhausted.

The word "exhausted" means very tired.
I am exhausted.
She felt exhausted after the game.

I'm beat.

This is a common expression to say that we are tired. We only use this in casual situations.

I am drained.

drain本身是排水的意思
在这里的用法很形象，你被抽干了，那自然就很累了
We have been working so much. I am drained.
I feel drained after working all weekend.

draining adj.
同样的意思，但是主语不一样
在这里主语应该是物
causing you to lose most of your energy; very tiring
He found the funeral service emotionally draining.

I'm wiped out.

similar to "I'm drained"

I'm worn out.

需要注意的是，这个短语用来表示在工作了很久以后很累
I have worked every day for the last 3 months. I'm worn out.
We have been so busy this week. I am worn out.
We also use the phrase "worn out" with clothes or things that we have used for a long long time and now their condition is not good.
I have been wearing these shoes for 2 years. They are worn out.

I'm burnt out.

This expression is only used to show that we are tired because of doing something over a long period of time. All of our energy has been used up. This expression has the feeling that we have lost our passion or desire to do something.
I have worked overtime every day for the past month. I am burnt out.
I think I need a vacation. I feel burnt out.
Remember that we cannot use this with short-term things.
I ran for an hour today. I am burnt out.
I ran for an hour today. I am exhausted.

burnout

名词
extreme tiredness, exhaustion, or a feeling of not being able to work anymore, caused by working too hard.
Burnout is common in many jobs, such as teaching.
Many students have burnout after taking their exams.

I'm fried.

It means that I am so tired, that my brain is fried. So, we are so tired that we cannot think well.

I'm spent.

This means that we have spent all of our energy. Therefore, we feel tired.

I am weary.

"Weary" is a more formal word that means tired. We are more likely to see this in books and writing.

I’m whacked.

I’m on my last legs.

I’m bushed.

I’m knackered.

I’m flat out tired.

I’m dead on my feet.

I’m running on empty.

#I’m running on fumes.

I’m tired out.

I’m dragging.

I’m stuffed.

I’m drowsy.

I can hardly keep my eyes open.

I’m off to bed.

I’m gonna hit the sack.

I’m all in.

I’m shattered.

I’m dead to the world.

I’m at the end of my rope.

taxing 形容词，指物需要花很多时间

difficult or needing a lot of thought or effort
I just need an entertaining read for the beach - nothing too taxing.
After the surgery, I couldn’t do anything too taxing for a while.