He China since he to China.A learned came B has learned comesC have learned came

问题补充：

He China since he to China.

A learned , came B has learned , comes

C have learned , came D has learned ,came

答案：

解析：句意：自从他来到中国以后，他就了解了中国。结合语境可知本句主句描述的是现在已经完成的动作，故用现在完成时态。从句中描述的是过去某时发生的动作，故用一般过去时态。选D。