吴先生与我并不相识，我也全然不知他为何会邀请我。
Mr. Wu and I did not know each other, and I had no idea why he invited me for lunch.
我们无从了解他们的出身，也全然不知其未来的归宿何在。
Their origins are beyond our knowledge and their future destinations are totally unknown.
虽然他接受起来可能有些困难，但他对此也不应该是全然不知。
He is likely to have some trouble with it, but he shouldn't be completely in the dark about it.
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