# Jaký je rozdíl mezi "si" a "se"?



## Odriski

Hi everyone!
The forum is a very amazing place for learning Czech! So I think I would like to ask any questions about Czech here rather than in my online discussing group as it is very inactive.
So here is my question today: What are the differences between "si" and "se"? I can see there are a lot of Czech words such as "dávat si", "sedat si", "dívat se", "pouštět se"...but the textbook doesn't tell me what is the difference between "si" and "se". So, are the two words exchangeable? If yes, in what case? If not, then in what case?
Many thanks for anyone who answer this question for me!


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## Tchesko

Hi Odriski,

No, these words are not interchangeable. Although they share the same English equivalents (_oneself / idea of reciprocity_), each has a precise grammatical function:

- "se" stands for a direct object (Accusative in the Czech case system);
- "si" stands for an indirect object (Dative in Czech).

Thus, we say:

- mýt se = wash oneself;
- mýt si ruce = wash one's hands (where "si" is a Dative with a possessive meaning, as explained by Enquiring Mind in this post).

Also note that some Czech verbs are pronominal, i.e. used with "se" or "si" without any explicit notion of reciprocity or reflexiveness, such as "dívat se" (to look), "bát se" (to be scared).

I'm sure there is much more to be said about "si" and "se" but these are the basics.


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## Hrdlodus

And "se" means "with" too.
But "with" can be "se" or "s".


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## Odriski

OK, thanks for your explanation, hope more explanation comes in


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