Hi xiaohanfromparis,
We understand you have some concerns about potential liquid contact with your Mac. We'll be happy to help!
You are right to be careful, contact with liquid can result in issues that wouldn't be covered under warranty. While we can't determine if there was enough liquid to reach internal components, we're happy to provide some information that may help.
First, if you haven't yet, cleaning your Mac and it's keyboard using the steps recommended on the following page, may help prevent liquid from entering and exposing internal components: How to clean your Apple products
If you're encountering issues with your Mac since this happened, taking it into a local store or service provider where it can be inspected first-hand by an Apple Certified Technician would be the best next step. You can find locations nearest to you and book an appointment online using the Apple Support app available for iOS devices, or using the following page to Find Locations.
For additional information about liquid contact check out the following page: Liquid damage to Mac computers and accessories not covered by warranty
We hope this helps!