用but造句三个，短一点

I can't help you, but my mom can.

我不会帮你，但是我妈妈可以。

I like this book, but it's too expensive.

我喜欢这本书，但是它太贵了。

I'd like to go to the cinema with you, but I am too busy now.

我想和你一起去电影院，但我现在太忙了。