If a person likes you, you may notice them staring at you, smiling at you, or trying to make contact with you. If someone has a crush on you, he/she will probably find excuses to touch you more than usual. If the person is shy, he/she might show attraction by avoiding you. If the person is more confident and forward, he/she might show attraction by giving you a lot of noticeable attention. If you often catch the person gazing back at you, this is a sign that they like you. Do they hold the stare intensely for several seconds? Do they shyly look away? Do they smile at you? All of these are signs that they like you. Read their eyes for interest. If they like you and they're staring at you in class, they probably won't be doing so with a blank expression. See if you can tell whether the person is legitimately checking you out, or simply staring off into space. If someone laughs at your jokes, even when they aren't funny, it may indicate that he/she likes you. It doesn't necessarily mean that the person has a full-fledged crush on you, but it often signals that there is some level of attraction. If someone likes you, you might notice their demeanor change. They will notice when you walk into the room, and they might make an effort to make a good impression on you. He/She might run his hand through his hair, or stutter a bit, or try extra hard to be funny. He/she might laugh a lot, or make an effort to be especially nice to you.  When they're with their friends, do they shrug you off, or do they invite you to hang out with the group? If they shrug you off, they probably don't like you. However, if they invite you to hang out, they probably at least find you an interesting person – and they may even have a "crush" on you. If you notice her friends giggling and whispering as you walk by, there's a decent chance that she likes you. If you notice him and his group of friends go quiet as you pass, it might be because they're talking about you! If you've seen this person staring at you once or twice, don't automatically...

TL;DR in Vietnamese:
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