我已经预订了明天的机票。

Wǒ yǐjīng yùdìngle míngtiān de jīpiào.

I have already booked the flight for tomorrow.

你需要提前预订酒店房间。

Nǐ xūyào tíqián yùdìng jiǔdiàn fángjiān.

You need to book the hotel room in advance.

我想预订一张去北京的火车票。

Wǒ xiǎng yùdìng yī zhāng qù běijīng de huǒchēpiào.

I would like to book a train ticket to Beijing.