This is a ticket stub.

这是一张票根。

Show your ticket stub at the entrance.

在入口处出示你的票根。

I'd better hold on to my ticket stub in case they won't let me in.

我最好还是自己拿着票根吧，以防他们不让我进来。

When you get on the transfer bus, just show the bus driver the ticket stub.

当你上了转乘的公共汽车时，就把这张票根给司机看。

I better hold onto my ticket stub in case you get in before I get back.

我最好拿着我的票根，以防你在我回来之前就进场了。