有两个英语问题，请教大家！在线等待！！

I think you had studied a lot before you took it. 过去完成时表示过去的过去。
She warned me that I would have an accident if I didn't take more care. 主句是过去时，所以从句从过去将来完成时，表示虚拟语气，如果不小心，就会有事故。

第一句应用过去完成时：had studied。
过去完成时表示在过去某一时刻或动作以前完成了的动作，也可以说过去的时间关于过去的动作。即“过去的过去”。可以用by, before等介词短语或一个时间状语从句(在复合句中，由时间连接词引导的状语从句叫做时间状语从句)来表示，也可以用一个表示过去的动作来表示，还可能通过上下文来表示。
e.g： By nine o’clock last night, we had got 200 pictures from the spaceship.

　　到昨晚9点钟，我们已经收到200 张飞船发来的图片。

第二句明显用过去将来时的 would have。因为主句warned为过去时，且用到的是虚拟语气。
虚拟语气用来表示说话人的主观愿望或假想，而不表示客观存在的事实，所说的是一个条件，不一定是事实，或与事实相反。虚拟语气通过谓语动词的特殊形式来表示。英语中的语气分为陈述语气、祈使语气、虚拟语气三类。
e.g：If I knew his telephone number,I would tell you.

　　如果我知道他的电话号码，我就会告诉你。（事实：不知道）

1. I think you had studied a lot before you took it.
2. She warned me that I would have an accident if I didn't take more care.

have studyed ；might have

1、had studied 2、would have