第1题：
It is seriously polluted.
The air is very clear.
There are few cars and factories.
It remains what it was ten years ago.
第2题：
第3题：
have longer sleep periods after work
make the light darker than usual
try to re-set their “internal clock”
pay more attention to their work
第4题：
that
when
what
which
第5题：
It has the largest number of customers.
It is grateful for its employees’ efforts.
It is successful in the market place.
It charges the least for its services.
第6题：
第7题：
$5.
$10.
$15.
$20.
第8题：
In a post office.
In a bank.
In a big store.
In a hotel.
第9题：
to pay for their own medical care
to help to live on their low incomes
to improve the national health care service
to solve one of the important political problems
第10题：
She’s a secretary.
She’s a manager.
She’s an engineer.
She’s a teacher.