实在太难 ( those sentences, after reading them two times i still have no idea, are too difficult for me.). 猜答案!(又不倒扣分, and there are some skills about it).
if you are a person speaking english everyday, pick/choose the sentence that sounds not correct to you. funny? It's ture that the "correct" answer choices for the GMAT'S sentence correction questions will probably not sound correct to you.