Hi DaesungKim,
1) When March begins, the ticket is no longer valid. It is not valid on the first of March, but it is valid in February, January and so on.
2) The sentence isn't correct - it actually makes no sense. It needs to be either "You should turn in your assignment tomorrow" (we don't "turn in" homework), or "You have until tomorrow to turn in your assignment" (tomorrow is the deadline, and you can submit it tomorrow).
3) Again, a wrong sentence. Replace "until" with "before" and it makes sense.