if 的条件句是主将从现即if引导的从句使用一般现在时而主句使用一般将来时,但是并非所有的句子但是如此,
1.比如主句也可以用祈使句
eg:if you come here next time,do take your baby with you because i miss him very much
2.有些词没有将来时态,只能用一般现在时
比如：decide ,want 等词
eg.if time permits,i want to have my hair cut