"About" is OK, and "of" is OK. "Of" sounds a little bit old-fashioned, though. "For" is wrong. The most natural preposition for a _warning_ would be "against:" "They warned me against pickpockets in the train station."

Yes. They are close synonyms. The American Heritage dictionary lists "calm, peaceful, placid, serene, tranquil" as synonyms, and doesn't mention any differences in meaning. "Peaceful" is a more common, more everyday word. "Tranquil" is slightly fancier, more literary.

If you are using a Mac, you can turn on PhotoBooth, and it will show your image back to you, as if in a mirror. On any platform, you can go to Google Meet, New Meeting, Instant Meeting, and it will show you image back to you, as if in a mirror. This will confirm that your camera is working, powered on, and not blocked or muted by your laptop itself. If that works, but someone on a video call can only hear you and not see you, it gets complicated. It's possible that you could have blocked your camera in your video calling tool. Just as you can mute your microphone, you can usually block your camera; there's usually a little camera button and it may have a line across it if you've blocked it. If the internet connection isn't good, your calling tool may automatically block video in order to save bandwidth. You should suspect this if your audio isn't clear, especially if it stutters or has gaps in it.

If you translate this literally into English, the result is an English idiom that means exactly the same thing. "I know it like the palm of my hand." I wonder which came first? It wouldn't surprise me if it came from Latin...

"Possible" and "probable" are everyday English. "Possibility" has a broad meaning. Oddly, "probability" has a narrow, almost technical meaning, and often refers to a specific percentage estimate. This is probably because of the mathematical theories of probability and statistics. Suppose you flip a fair coin ten times in a row. The two sides of a coin are called the "head" and the "tail." You can say: "It is possible that you could get 'heads' ten times in a row." "However, is probable that you would get 'tails' at least once." "Getting ten 'heads' in a row is a possibility.." You could NOT say "Getting 'tails' at least once is a probability." You COULD say "The is a 99.9% probability of getting 'tails' at least once."

En el contexto de ropa, creo que podemos decir "llevar" para "usar." La temperatura esta alta, hoy yo llevará una camisa de mangas cortas. ¿Asi es?

I don't think it has anything to do with the presence of adjective. If you left out the word "terrible," the proper phrasing would still be "a sin and an immorality." (The indefinite article changes from "a" to "an" for euphony, when preceding a word that begins with a vowel sound). You could avoid the indefinite article by changing "sin" and "immorality" to their adjectival forms, though: "it is also sinful and immoral."

No. The sentence is in the present tense. It telling about present possibilities. It is talking about things they can do now. "Pursued" would refer to something they did in the past. If the facility had closed, you could say it's sad, because it had been a place where they pursued knowledge. "To pursue" is the natural choice, but here are some other possibilities: ...a place for pursuing knowledge... ...a place where they can pursue knowledge... ...a place for the pursuit of knowledge...