/1.It is easy to get accepted to this university. Is fine. (There was a typo, univeristy instead of university, but it's obviously a typo.) /it is easy getting accepted to this university. Getting accepted to this university is easy. We capitalize the first letter in the sentence, and as "It" refers to the gerund, "Getting..." it's more natural to just take it out and put what amounts to the subject of the sentence (Getting accepted...) at the beginning. /does think about means consider. Doesn't mean anything. /it isn't think something carefully. Doesn't mean anything. /if you want to express you think something carefully, you should say think over it? Is getting close to meaning something, but what is unclear. I think this might be meant to be, "If oyu want to express that someone should carefully thing about something, you should say, "Think over it." are they correct? /I have thought about it./ I have considered it. Both of these work, and they mean essentially the same thing.