I went with what sounds right, even though if someone had asked me why I "chose" it, I wouldn't have been able to elaborated it. I think it sounds ok for conversational english. It would be "elaborate" though and not elaborated. Or if you are trying to sound more professional you could say: I chose the answer that sounded correct, but if asked I wouldn't have been able to elaborate on why I chose it.

First, i would say we don't really use the term "pocket money." It sounds like you are referring to an "allowance" given to a child or teenager from a parent. (Many) think that young people become more serious and sensible (about money once they begin to receive an allowance). (In my opinion,) parents should give their children (an allowance) and (not be concerned with how) they spend it Teenagers buy clothes because (looking fashionable) is very important today. We pay for mobile phones and internet (service) because without it we can not study. Moreover(,) many people (understand) how difficult(it is) to earn money (at our age).

yes this is correct or you could say "when can i meet you?" "when should i meet you?"

lining up the sights means being able to align the gun/arrow with your eye and the target so you can hit it. If your sights were not aligned you would miss. Changing a tire means removing the wheel from your car and replacing it. Changing a tire is a relatively easy and common thing so they are saying that hitting a bulls eye is even easier.

It depends on the area but i think generally Coca Cola/Pepsi, lemonade, fruit juices and iced tea are universal

slowly falling ill I think it would be based on the rest of the sentence

I believe here it is the act of recording and combining meteorological data

military rule=the military runs Burma rather than a democracy cyclone=similar to a tornado Its hard to tell you what the meaning of the sentence is because I do not know what IT is. Example: "It may finally fall victim to Burma'a building binge." What is it?