but i am not good at korean-grammar like you''re not good at your mother tongue. <-----i meant you couldn't be good at English grammar, sorry. and you also could be good at it if your major is English. but normal people aren't...so i said this.^^

you asked 3cases. but No.1 i can't explain this. i don't know what you're saying. i need full sentence. and no.2 is this one of conjugate? well, though i am korean. but i am not good at korean-grammar like you''re not good at your mother tongue. yes. there is a similar one in English. "might and may" but i recommend might rather than may. but, actually, there are some cases similar between (~일)것이다 and might. i mean that if you might be sure for a case, you could use this one. the conjugate "might" is used very multiful, doesn't it? i literally say this. Don't think Korean as you think. i mean the method you use your mother tongue. though i'm saying (~일)것이다 is similar to "might", but this is on guessing only. another cases? it could be different. i'm quite worrying about this and no.3 it also needs full sentences. thru what you said, i don't know what you wonder. i hope that this could help you. have a nice day.

ok 겠 is used for yourself, in first person. It means you will do something,, but it doesnt mean the same in second person. next, (으)ㄹ 것이다 just conjugates the verb in future tense. Its just a normal conjugation heh. and finally, (으)려고 하다 means "intend to do something/going to do something". Its just a matter of words for example, try to see the difference in the following sentences.. "i will study" and... "i am going to study". I hope that helps.. lol