条件状语从句Adverbial Clauses of Conditions(1) if, unless(除非 if not.)eg. _ we have enough evidence, we cant win the case. _ I was in charge, I would do things differently.(2) only if 只有,只要eg. We will go only if it clears up./ Only if it clears up, _ Only if we work together_只有一起努力,我们才能成功。区分:only if Vs. if only _eg. If only I were a superman. /If only I could fly./If only I had taken his a