You may take part in the school party ___ you keep quiet .

题目

You may take part in the school party ___ you keep quiet .
A if B unless 选择哪个呢?求二者的详细区别.急,

答案

选a
if 是肯定的条件：如果你想去学校派对的话,你必须保持安静
unless多用于否定的条件：如果用unless的话,这句话应该是这样的：
You may NOT take part in the school party unless you keep quiet.
如果你不保持安静 就不能去学校派对