You pay a small maintenance charge once a month.
举一反三
- —__________ do you go to see a film? — Once a month.
- —_______ do you visit your parents? —Once a month.
- ________ you pay in advance, we won’t charge you for delivery.
- "Will you pay cash or shall I charge it to your ______ ?” asked the salesman.
- You needn't to pay for the excess baggage charge for your overweight luggage.