由if引导的假设语气的问题,如：If i had a lot of money,i would buy a car.

不行,根据虚拟语气的规则,你所指的句子为主句.而你所指句子是对现在的虚拟,主句只能用should,would,could,might+动词原形.所以不能用I bought.
可以看看高二上期选修6后的语法讲解,记住那个表格就可以解决If的虚拟主从句的变化问题.