a monthly fee的用法和样例：
- An ISP provides you with access to the Internet, usually for a monthly fee.
- If you want to watch cable TV programs, you'll have to pay a monthly fee.
- No charge for online aspect of PSU on XBOX 360. There will be a monthly fee for PS2 and PC users.
- Banks generally charge a monthly fee as well as a per-transaction fee for merchant accounts.
- Paig: Yes. I pay a monthly fee of 1,500 NT, and that includes the 3)locker fee. I don't have to pay a membership fee.