...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!
He blamed President for causing the migrant crisis that's seeing large numbers of people flee into neighboring countries.
定语从句用一般现在时,是表示他(过去)指责总统导致了现在正在上演的危机?用现在完成进行时岂不是更好?