比 (bǐ) is a preposition used to indicate a comparison where there is a difference in degree or quality between two entities. The structure for using 比 (bǐ) is relatively straightforward: Subject 1 + 比 + Subject 2 + Adjective. This structure is employed to express that subject 1 has more or less of a certain quality than subject 2.

他比我高。
(Tā bǐ wǒ gāo.)
He is taller than me.

Here, the speaker compares height (高, gāo – tall) between themselves and another person. The use of 比 (bǐ) clearly indicates that the speaker is lesser in the quality being discussed (height, in this case) compared to the other person.

Elaboration with Adverbs

You can further elaborate on comparisons by adding adverbs such as 多 (duō) meaning ‘much’ or 一点 (yīdiǎn) meaning ‘a little’. This helps in specifying the degree of difference.

她比我聪明多了。
(Tā bǐ wǒ cōngmíng duō le.)
She is much smarter than me.

In this sentence, the adverb 多了 (duō le) is used to emphasize the significant difference in intelligence between the two subjects.

Using 跟 (gēn) for Comparisons

While 比 (bǐ) is used to highlight differences, 跟 (gēn) is often used to denote similarity or to compare actions between subjects. The structure when using 跟 (gēn) is Subject 1 + 跟 + Subject 2 + Verb/Adjective. It’s essential to note that 跟 (gēn) does not inherently imply a difference in degree like 比 (bǐ) does.

我跟他一样高。
(Wǒ gēn tā yīyàng gāo.)
I am as tall as him.

This structure highlights that the two subjects share a similar attribute (height, in this example) without any indication of one being more or less than the other.

Comparative Sentences Involving Actions

跟 (gēn) can also be used to compare actions between two subjects, indicating that they are doing something together or in a similar manner.

我跟我的朋友一起去看电影了。
(Wǒ gēn wǒ de péngyǒu yīqǐ qù kàn diànyǐng le.)
I went to watch a movie with my friend.

Here, the sentence isn’t directly comparing an attribute of two subjects, but rather it is stating that the action of going to watch a movie was done together with someone else.

Practical Usage and Exceptions

In everyday conversation, the choice between 比 (bǐ) and 跟 (gēn) can greatly change the nuance of the sentence. It’s also worth noting that there are exceptions and additional structures that can sometimes complicate their usage. For example, while 比 (bǐ) generally compares differences, it can be used in a rhetorical or idiomatic expression to denote extremeness without a direct second subject.

他比天还高。
(Tā bǐ tiān hái gāo.)
He is extremely tall (literally: taller than the sky).

Conclusion

Mastering the use of 比 (bǐ) and 跟 (gēn) in Chinese not only enhances your ability to express detailed comparisons but also deepens your understanding of the intricate ways in which Chinese handles descriptive relationships between subjects. Practice using these prepositions in various contexts to better grasp their nuances and applications in everyday Mandarin.