Advanced time-related prepositions
Q1. Please respond ___ a week
WITHIN means during the period. A week is the limit. Responses are anticipated.
Q2. Submit the report ___ Friday
BY indicates deadline. Friday is the endpoint. Reports are submitted.
Q3. Wait here ___ further notice
UNTIL marks continuation to a point. Notice is pending. Waiting continues.
Q4. ___ Christmas, all will be revealed
COME CHRISTMAS is an idiomatic future expression. Revelations await. Patience is tested.
Q5. We must finish ___ the deadline
AGAINST THE DEADLINE suggests urgency. Time is the opponent. Finishing is required.