How to use 对 (duì) and 跟 (gēn) as prepositions in Chinese grammar

Prepositions are difficult in any language, and Chinese is no exception. One pair of Chinese prepositions that seems to trip up native English speakers quite a lot is 对 (duì) and 跟 (gēn). They don’t seem to map to any prepositions in English, but they come up a lot in Chinese grammar and can control the meaning of verb phrases in quite significant ways.

The main difference to focus on is that 对 usually implies a one way relationship, whilst 跟 is used for two-way relationships. In other words, 对 expresses that the action of the verb goes in one direction (from subject to object), whereas 跟 expresses that it goes in both directions.

It might help to rigidly think of 对 as meaning “to”, and 跟 as meaning “with”. Sometimes this will produce strange sentences if you translate into English, but this can often be a good way to build up a stronger sense of Chinese grammar.

对 and 跟 with 说 (shuō)

A very common use of 跟 and 对 is with the 说 (shuō) - “to speak”. 对 and 跟 are often interchangeable when used in sentences about telling people things, or saying things to people. For example:

A lot of people would say that there is no real difference between 跟 and 对 in this situation, but we tend to believe in the rule of ’no true similes’. That means that even if native speakers can’t quite say what it is, there will always be some kind of difference between two different words, at least in certain contexts. See below for more detail on that.

In general though, you can assume that using 对 or 跟 with 说 doesn’t really make a significant difference. More examples:

In each of these examples, you could swap 跟 and 对 and there wouldn’t be much difference in the meaning. Note that these sentences are all about telling or saying things to people. Those are the situations when 跟 and 对 are interchangeable. Otherwise, you’ve got to pick more carefully.

When the preposition should be 跟 and not 对

As mentioned above, 跟 is often used when the action of the verb is two-directional, or there is a two-way relationship between the subject and object. More intuitively, 跟 is also used to express things being done together or with other people. Here we’ll look at two situations involving 跟 that can be tricky to get used to.

Using 跟 for discussions and explanations

We explained above how 跟 and 对 can be interchangeable when used in sentences about “telling” and “saying to”. However, there are many situations that involve speaking where the choice of 跟 and 对 does make a big difference.

One of those is sentences about discussions, explanations or revelations. In other words, if there is a focus on a conversation or two-way exchange, the sentence is unlikely to use 对. Have a look at some examples:

In these examples, if you swapped 跟 for 对, the sentence would become quite strange or just plain wrong. For example “我对你讲” has a sense of “I am talking to you and you are listening” - it becomes a one-way action rather than the two-way action implied by 跟.

If you say “我有一件事想对你说” rather than the sentence above, it becomes “I want to tell you something”, but focuses much more on the one-way action of telling, rather than any conversation that might surround it.

The sentence with 商量 simply can’t use 对, otherwise it would be like saying “I’d like to discuss something to you”. A discussion is a two-way action, so it only makes sense with 跟.

Using 跟 for comparisons

Another common use of 跟 as a preposition is to make comparisons between two things (when used like this it’s the same as 和). This can confuse native English speakers who might expect to use 对, as “to” is often used to make comparisons in English. In Chinese, though, you say that “A and B are different” or “A is the same with B”. Have a look at some examples:

Remember that Chinese prefers to express similarities and differences as a two-way relationship (“these two things”), whereas English tends to express them as a one-way relationship (“this thing to that thing”, “this thing from that thing”). Some more examples to reinforce this point:

Notice how all of these comparisons can be expressed using 跟 in Chinese (they could also be expressed with 和), whereas English has a few different prepositions for the different situations.

When it should be 对 and not 跟

In some situations, the preposition has to be 对 and not 跟, otherwise the sentence would be incorrect. These are situations with a one-way action or one-way relationship from subject to object. Have a look at some examples:

Notice how each of these sentences is about a one-way effect or action. The object is affected by the subject, but not the other way round (or at least the sentence doesn’t mention any action in the other direction).

When using 对 or 跟 changes the meaning

There are situations where using either 对 or 跟 would be grammatically valid, but the meaning is significantly different. For example:

As you can see, the difference between a one-directional action and a two-directional one is very different. Another example:

The difference here isn’t so significant, but it’s still clear. In the first sentence with 对, only the politician is doing the talking. When 跟 is used, it seems that a two-way discussion is going on.

We said above that when used with 说, 对 and 跟 are pretty much the same. However, if you change the verb a little bit, there is a more obvious difference:

There is a clear-cut difference between the meaning of those sentences in Chinese and English, and you can see how the use of 跟 (“with”) vs 对 (“to”) makes this happen.

Summary of 跟 and 对 as prepositions

• Very similar / the same when used with 说 to talk about “telling” or “saying to”.
• 跟
  • Can be thought of as meaning “with”.
  • Usually implies a two-way action.
  • Can often imply a continuous action or exchange.
• 对
  • Can be thought of as meaning “to”.
  • Usually implies a one-way action.

See also

• Comparing “gen” and “dui” - Chinese Grammar Wiki