about "as if"

[hhchen]

Hello,

In each case, which is correct? Why?

1. He smiles at the foreigners as if he knew them.
He smiles at the foreigners as he had known them.

2. He looks pale as if he saw a ghost.
He looks pale as if he had seen a ghost.

Thanks for responding to my question.

[Tdol]

Which do you think are right?

[hhchen]

In my opinion, in each case, the second one is correct. But not sure. Thanks.