9. I do not know how to fill out the exchange form.
我不知道怎样填写兑换单。
还能这样说：
Can you give me some help to finish the exchange form?
Could you tell me what I should do to fill in the exchange form?
谚语：
A leopard can't change its spots.
积习难改。
10. Opening a checking account may be economical for you.
对您来说，开立一个支票账户是实惠的。
还能这样说：
It will be better for you to open a checking account.
That checking account will be affordable for you.
应用解析：
be economical of one's time 节省时间；
an economical housewife 一个节俭的家庭主妇
11. Good morning. Are you being attended to?
您好，有人接待您了吗？
还能这样说：
Good morning. Have you been waited on?
Good morning. Are you being helped?
应用解析：
not attend 无人值班；
attended substation 值班员变电所
12. You should fill in a form here first.
您首先需要在这儿填个表格。
还能这样说：
Please fill out a form here first.
First, you need to fill out a form.
谚语：
The cask savors of the first fill.
先入为主。