▎所, suǒ, (Ptc), Verb Marker

Function The particle 所 marks the main verb of a relative clause, which modifies a noun.

1 這本書所介紹的方法，我早就學過了。

Zhè běn shū suǒ jièshào de fāngfǎ, wǒ zǎo jiù xuéguò le.

I have long since learned the methods outlined in this book.

2 他們所關心的價格問題，其實我們覺得並不重要。

Tāmen suǒ guānxīn de jiàgé wèntí, qíshí wǒmen juéde bìng bú zhòngyào.

The issue of price that they are concerned with is actually not so important to us.

3 我們已經把王先生所訂購的產品寄出了。

Wǒmen yǐjīng bǎ Wáng xiānshēng suǒ dìnggòu de chǎnpǐn jìchū le.

We have already mailed out the products Mr. Wang ordered.

Usage The usage of 所 is more formal, and its use is completely optional.