I have explained everything that i can to you.

I have explained to you everything that I can.

没改动原有的意思~~~~~`

can 后面加do 变为 I have explained everything that i can do to you我能把我所解释的都向你解释了

后面用过去时could或did来替换can
因为主句是现在完成时,我已经向你解释了(过去)所能解释的一切

could 保持时态一致。

去掉to you

I have explained everything that I can say to you .你觉得呢?