z

Sounds kind of like "ds" in "bids", but voiceless.

zì​jǐ

oneself

自己

zài​jiàn

goodbye

再见

IPA: [t͡s]

c

Sounds kind of like "ts" in "cats".

word

cè​suǒ

bathroom

厕所

IPA: [t͡sʰ]

s

Sounds like "s" in "sick".

four

sān

three

IPA: [s]



Single-syllable audio courtesy of the AllSet Learning Chinese Pronunciation Wiki, used with permission.

HSK word audio courtesy of Audio-cmn. (CC BY-SA 3.0)