问题
选择题
_________ you take an active part in physical activity ______ be able to keep fit and stay healthy.
A．Only if; you will
B．Only if; will you
C．Unless; you will
D．Unless; will you
答案
答案：B
题目分析：考查倒装句：句意：只有你积极的参加体育活动，你才能保持健康。Only后面接状语从句的时候，主句应该用部分倒装，助动词will放在主语前面，选B。
