关于wish从句和 would rather从句,老师在讲虚拟语气时讲过 wish和 would rather的用法是：现在时和将来时推成过去时,过去时推成现在完成时.可是有一道题i'd rather you ( ) right away.A leave B left C will leave D to leave 老师讲这个道题的时候说,选B 因为与现在事实相反,应该推成过去时,又说,如果这道题如果将would rather 改成wish就应填would leave,也就是说wish,是不是老师自相矛盾了呢?还是我理解错了?

你要换个老师了.你的老师有点糊涂.:-)
"现在时和将来时推成过去时"是基本对的(见下面讲的would)."过去时推成现在完成时"是错的.过去时应该推成过去完成时.例如:
"I would rather you had kept the craze, so that you had kept the practice which went with it!"
(托马斯·哈代《德伯家的苔丝》里的一句话)
用过去完成时表示太晚了,来不及反悔／改变了.用过去时表示还能改变.
I'd rather you left right away.
意思就是说如果你现在就离开还来得及.
wish的用法和would rather基本上是一样的,也可以用过去时.例如：
"There! That's he coming! How I wish you were not here!--that is, how awkward--dear, dear!" she exclaimed, with a quick ascent of blood to her face, and irritated with Dick rather than the vicar, as it seemed.
(托马斯·哈代《卡斯特桥市长》)
这里”How I wish you were not here!”用的就是过去时.
wish和would rather都可以在后面加would,应该是从将来时推过来的.例如：
I would rather you would say that the greatest asset the Kremlin has is the present approach of those in the Senate who are trying to sabotage the bipartisan foreign policy.
(杜鲁门总统在美国国会作证时的答话.)
所以
I'd rather you would leave right away.
I wish you would leave right way.
I'd rather you left right away.
I wish you left right away.
都是对的.