puzzle

Yes, it's correct. [And it's also terribly frustrating. I know people who are certain that there is some mysterious little imp who steals one piece from every puzzle box just before it's sealed.]

Hi,
Have you ever tried to solve a puzzle and when you are down to the last piece, you realize it's missing?

Is the above correct? Yes. It's a good example of very natural, everyday speech.

If you wanted to write a lot more carefully, you could write
Have you ever tried to solve a puzzle and, when you were down to the last piece, realized it was missing?

Philipthere is some mysterious little imp who steals one piece from every puzzle box

There is, Philip, but not before it's sealed. It's once it's home, and it's called a cat.

Philip mysterious little imp who steals one piece from every puzzle box just before it's sealed.]

HAHA... That's quite possible. Why have I never thought of it?

Clive. That's exactly what bothered me. The tense inconsistency. I think the past tense looks a bit better. Thanks.

Hi,

Yet as I said, in everyday, casual speech, we often are relaxed about such matters.

Clive