9. How much is the rent per month?
月租金是多少?
还能这样说：
When is the rent due per month?
How about the rental fee per month?
应用解析：
a month of Sundays 很长的时间;
by the month 按月;
month after month 一月又一月;
month by month 逐月，月月
10. The rent is due no later than the twelfth of the month.
租金在每个月的12号之前付清。
还能这样说：
You need to pay the rent before twelfth of the month.
The latest date for paying the rent is twelfth of the month.
谚语：
Never too late to mend.
亡羊补牢犹未晚矣。
11. This house is for rent.
此房出租。
还能这样说：
This house is to be let.
It's a house to let.
12. It's really a bargain.
租金很便宜。
还能这样说：
It's low rented.
The house was cheap to rent.
应用解析：
bargain on doing sth. 商定做某件事;
bargain over the price 讨价还价;
a bad bargain 吃亏的生意