Depends on what drugs they are taking, some drugs can make you happy and energetic, some can make you sleepy or depressed. Look at their pupils (black part of the eye), if they seem too big or too small in normal lighting, something is acting on their body. If their personality is way different then normal that is a good way to tell.
not unless you are supposedly a virgin and you have sex with him. or if your friend tells him. those are the only two surefire ways to know when someone has cheated but if not by those ways and if u dont tell him then no he wont know.
Raluca Negrea
i mean can some one tell me
Not without some idea of that you are talking about.
Just get her or him in a place where you'll have some privacy and tell them
Acts 7:60 But the story is in Acts 7:1-60
You may notice symptoms such as red or glassy eyes, slower reaction times, impaired coordination, and altered speech patterns. Additionally, the person's behavior may be more relaxed or giggly than usual.
Tunguska Explosion
yes but some people will tell ya
Often you cannot tell. Someone who is gay will tell you at some point if they come to terms with their sexuality--and if you have shown yourself to be someone they can trust with this knowledge.
some people are kinda messed up and have to compulsively follow someone- tell someone if they do that's the most important thing and if you think someone's stalking you stay in a busy area and/or tell someone.
Yes you can tell if someone is in love with you. You can tell by the way him or her are acting, They may even flirt with you. It worked with me!