I wonder if I can board the plane with this return ticket.

我想知道我是否可以用这张回程机票登机。

All I got is a return ticket.

只剩下一张来回票了。

How much is the return ticket?

往返机票是多少钱？

May I see your return ticket?

能看一下你的往返票吗？

I would like a return ticket.

我想要张往返票。