英语中“彼此彼此”怎么说？

same here.
me too.

彼此彼此: same here

"I think I ate too much."-"Same here. I did to."
"我想我吃得太多了。"--"彼此彼此。我也吃得太多了。"
Same to you.
彼此彼此。
You must have taken a lot of trouble about it.--So must you!
您辛苦啦！－彼此彼此！
They chipped at each other.
他们彼此相互嘲笑。
Each other or one another
互相，彼此
They have mutual admiration and then mutual love.
他们彼此倾慕，尔后彼此相爱。
We cemented our friendship.
我们巩固彼此的友谊。
They are affectionate to each other.
他们彼此的感情深厚。
They were estranged from each other.
他们彼此变疏远了。
They were hard by each other.
他们彼此很亲密。
We write to each other regularly.
我们彼此经常通信。

如果别人用的是一般动词,回应则用,so do i/so did i/ so have i/根据时态

如果是BE动词,回应则用so am i/ so was i/也要根据时态..

或者直接说same as you...也不错。

彼此彼此是很口语化的说法。而相对应的英语口语是：likewise.
例如：
--Have a nice day
--Likewise(你也一样)

me too
you too

the