It's no use your pretending that you didn't know the rules.
It's=It is.
为什么这里使用了didn't know一般过去时时态?
为什么不是don't know与前面的It is呼应呢?
是否可以改成...
It's no use your pretending that you haven't known the rules.
请教老师分析!
It's no use your pretending that you didn't know the rules.
roughly means:
It is meaningless that you pretend that you didn't know the rules.
(1)...that you didn't know the rules.
happened sometime in the past
(2)...right now you are pretending (1)