Well, it depends. There is no clear cut way to identify it unless you have actually seen someone who is truly high, or if you yourself have been high, but it is usually identified by red eyes, lowered eyelids, etc. The best way to tell is to buy an test kit for drug use.
No you cannot. It is impossible to tell from a persons eyes that they are pregnant.
You can tell someone is high just by looking at their eyes. They may be red if eye drops weren't used, even if they were you can look right at the pupils, if they're dilated, chances are they're high.
one of his eyes will twitch or he is looking at you strange even if he is looking in your eyes
No, but there are physical non-verbal signals that do tell when you lie. One of the big ones is not looking a person in the eyes, but looking down/shifting the eyes.
looking in their eyes is the best bet. the eyes tell all
If it is floating around, is whitish looking, and its eyes are pale.
You can move and see if the persons eyes follow you.
No, but if you catch her looking at you a lot, it may be a way to tell that she already likes you.
No, but there are physical non-verbal signals that do tell when you lie. One of the big ones is not looking a person in the eyes, but looking down/shifting the eyes.
No.
Smoking cannabis doesn't really have any lasting effects, so the only real way to tell is to catch them smoking or acting high (red eyes, looking confused or "out of it", paranoia). That or somehow get some of their urine and test it.
Not really. You can't tell if she loves you. However, if her pupils are very large when she looks at you, she is almost certainly attracted to you