1.bill n.纸币，账单

pay my bill with bill of small denomination 用小面值纸币来付账单。

2.mail n.& vt.邮递，邮送

E-mail 电子邮件

post office 邮局

3.extention n.延期；分支

apply for extention of paying for the bill

申请账单延期支付

4.prove vt.证明，检验，显示

-I dare say...

-Don't say it. Prove it!

-我敢说……

-别说，证明给我看！