我生病了，要请假一天。

Wǒ shēngbìng le, yào qǐngjià yìtiān.

I'm sick, I need to request a day off.

只要你星期五以前把报告写完你就可以请假。

Zhǐyào nǐ xīngqīwǔ yǐqián bǎ bàogào xiěwán nǐ jiù kěyǐ qǐngjià.

As long as you finish your paper by Friday, you can ask for leave.

我头有一点疼，想请假回家休息一下。

Wǒ tóu yǒu yìdiǎn téng, xiǎng qǐngjià huíjiā xiūxi yíxià.

I have a little headache, I want to ask to go home and rest a little.