pronoun, particle, verb, preposition, noun, adverb · this (adjective or demonstrative used before a noun to specify which one)

我不喜欢这个颜色，请帮我换一个。

pronoun, noun · demonstrative pronoun referring to the entity near the speaker or the one being discussed; this.

这个计划非常周全。

pronoun, verb, preposition, punctuation · this thing or person already mentioned or present (pronoun)

这个多少钱？