你的登机牌上会有你的座位编号。

Nǐde dēngjīpái shàng huì yǒu nǐde zuòwèi biānhào.

Your boarding pass has your seat number.

我的登机牌不知道放在哪里了。

Wǒde dēngjīpái bù zhīdào fàng zài nǎlǐ le.

I don't know where I put my boarding pass.

请准备你的登机牌给职员检查。

Qǐng zhǔnbèi nǐde dēngjīpái gěi zhíyuán jiǎnchá.

Please prepare your boarding pass for the staff to check.