in ieturn

是不是in return？意思：作为回报

He gives me an apple,in return,I give him one.
他给了我一个苹果，作为回报，我给了他一个。

或者加一个for : in return for

In return for his apple,I give him one.
为了回报他给我的苹果（谢谢他给我苹果）我给了他一个。

in turn
adv.
依次, 轮流

n.依次,而,又