运行中除氧器含氧量增大的原因有哪些？

Trudy’s class has an English newspaper. The students write stories, articles and poems for it. Then they type and print their works out. The teacher posts everything on the wall so that it looks like a large, open newspaper.
One day Trudy said to the teacher, “Most newspapers have advertisements. Can we have some small ads in ours?” The teacher thought this was a very good idea. She made Trudy the advertising manager and Trudy asked the other students to offer things for sale in the newspaper. Here are some of the ads she received.

GOOD HOME WANTED: Six lovely cats need good homes. They are the cutest things you’ve ever seen. Free to the right person.  See John.	CONCERT TICKETS: Has anyone got an extra ticket for the Raiders concert next week? I’m looking forward to and will pay well for a good ticket.  See Sheila.
Stationery For Rent: Anyone who has left his stationery at home, please come to Mike. No charge. But make sure to return in time.	LOST: A silver ring with a blue stone in it. Reward. See Patricia.
WANTED PC: In good condition. Must be at least a Pentium. See Alan.	PETER’S HOMEWORK SERVICE: Help you solve the problems in your homework.  Not expensive. Quick service.  See Peter.
WORK WANTED: Strong boy willing to work in the garden or do housework. 3 hours a week. Not expensive.  See Tom.	Exchange Magazines: If you are interested in Chinese magazines and have science magazines at hand，please come to Nina.

小题1:Who wanted to put advertisements in the newspaper?

A．Trudy.

B．The teacher.

C．Some of the students.

D．Alan.

小题2:What is Tom willing to do?

A．To do other people’s homework.	B．To work in the garden or do housework.
C．To sell six cats.	D．To fix broken PCs.

小题3:What does Alan want to buy?

A．A lovely cat.	B．A silver ring.
C．A PC in good condition.	D．A ticket to the Raiders concert.

小题4:Why will Sheila pay well for a Raiders concert ticket?

A．Because she is thinking about going to the concert.

B．Because she is looking forward to going to the concert.

C．Because she doesn’t have homework to do.

D．Because her friends are going to the concert.

小题5:What will Patricia give the person who finds her ring?

A．Nothing.

B．Another ring.

C．A ticket to the Raiders concert.

D．A reward.