这勺子是你的吗 was rejected.
What about: 这是勺子你的吗 ？Is this wrong, if so why?
I don't know why, but this just sounds weird to weird to. (I'm by no means fluent though
I added the measure word 把 after 这 and it was accepted,
why does it need 了 after spoon?
It's 子 which is part of the 词 for spoon.