A complete sentence can serve as the subject without any particular marker. It should be noted that a comma can be used after a sentential subject, especially when the subject is long.
在中国，丈夫做家务，是一件很平常的事。
Zài zhōng guó，zhàng fū zuò jiā wù，shì yī jiàn hěn píng cháng de shì。
In China, husbands doing housework is a very common thing.
(丈夫做家务 is the subject.)
Expletive ‘it’ in English has no counterpart in Chinese. This means that a sentence with a sentential subject may have different word orders in English and Chinese.
儿子不听她的话，让她很难过。
ér zǐ bú tīng tā de huà，ràng tā hěn nán guò。
It saddens her (= makes her sad) that her son does not listen to her.
In English, a sentential subject is frequently introduced by the phrase ‘(the fact) that . . .’. Note that such a phrase is not used in Chinese. The phrase ‘the fact that’ does not have a counterpart in Chinese.
王先生喜欢李小姐不表示李小姐也喜欢王先生。
Wáng xiān shēng xǐ huān lǐ xiǎo jiě bú biǎo shì lǐ xiǎo jiě yě xǐ huān wáng xiān shēng 。
The fact that Mr Wang likes Miss Li does not mean that Miss Li likes Mr Wang, too.
[1] Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.
[2] Teng, W. H. (2016). Yufa! A practical guide to Mandarin Chinese grammar. Taylor & Francis.
