Someone tells you their son graduated basic Marine training a couple of months ago.
“I didn’t know he was a marine.”
Now, this is grammatically correct, and sounds better (to me) than the more logical:
“I didn’t know he is a marine.”
However, presumably, unless the person’s son has been very quickly booted out, he is still a marine. Yet the natural thing in English seems to be to use the past tense of “to be”, apparently to agree with “I didn’t…” but thereby incorrectly implying that he is no longer a marine.
I’ve always found this awkward. Can anyone explain why this is the preferred way to do things?