这本书的内容比较复杂，不太适合初学者。

Zhè běn shū de nèiróng bǐjiào fùzá, bú tài shìhé chūxuézhě.

The content of this book is rather complicated and not very suitable for beginners.

这道题目挺复杂的。

Zhè dào tímù tǐng fùzá de.

This question is quite complicated.

这个问题有点复杂，我们慢慢讨论吧。

Zhège wèntí yǒudiǎn fùzá, wǒmen mànmàn tǎolùn ba.

This problem is a bit complicated; let’s discuss it slowly.