请教下面句子是对过去的虚拟还是对现在的虚拟?
He talks as if he had known John since boyhood.
请问这句话中，虚拟语态是对过去的事情进行虚拟还是对现在的事情进行虚拟呢？
现在有两种说法：
对过去的虚拟；
对现在hsa know John since boyhood的虚拟。