从所给的四个选项中，选择最合适的一个填入问号处，使之呈现一定的规律性：(). A.A

In the 13th century, the Italian traveler, Marco polo , traveled a long way to China , During his stay in China , he saw many wonderful things . One of the things he discovered was that the Chinese used paper money . In western countries , people did not use paper money until the 15th century . However , people in China began to use paper money in the 7th century .

A Chinese man called CaiLun invented paper almost 2000 years ago. He made it from wood . He took the wood from trees and made it into paper . He then put these pieces of paper together and made them into a book .

Now paper still comes from trees . We use a lot of paper every day ! If we keep on wasting so much paper , there will not be any trees on the earth . If there are no trees , there will be no paper . Every day , people throw away about 2800 tons (吨) of paper in our city . It takes 17 trees to make one ton of paper . This means that we are cutting nearly 48000 trees every day . Since it takes more than 10 years for a tree to grow , we must start using less paper now . If we don’t , we will not have enough time to grow more trees to take the place of those we use for paper .

So how can we save paper ? We can use both sides of every piece of paper , especially when we are making notes .We can choose drinks in bottles instead of those in paper packets . We can also use cotton handkerchiefs (手帕) and not paper ones . When we go shopping , we can use fewer paper bags . If the shop assistant does give us a paper bag, we can save it and reuse it later .

Everyone can help to save paper . If we all think carefully , we can help protect trees . But we should do it now , before it is too late .

小题1:When he was in China , Marco polo ___________ .

A．discovered CaiLun invented paper

B．learned to make paper

C．saw many wonderful things

D．told people about it小题2:About _______ tons of paper are thrown away every day in our city.

A．1700

B．2000

C．2800

D．48000小题3:Which of the following is NOT the way of saving paper ?

A．To use both sides of every piece of paper

B．To use the paper bags from shops more than once

C．To use cotton handkerchiefs instead of paper ones

D．To grow more trees小题4:Which of the following is NOT TRUE ?

A．If we keep on wasting paper , we will have no paper to use

B．The Chinese used paper money much earlier than the people in western countries

C．About 48000 trees can be used to make 2800 tons of paper

D．It is never too late to plant trees for paper .小题5:Which is the best title (标题)of the passage ?

A．Saving Paper

B．The history of Paper

C．Cotton Handkerchiefs Back Again

D．CaiLun , the Great Inventor

下列哪种传染源最常引起菌痢爆发（）

A.病原携带者

B.急性典型痢疾

C.中毒性痢疾

D.急性非典型痢疾

E.慢性病人

一般在设备布置图的左上方要画出安装方位标，作为确定设备安装方位的基准。

属于原核生物的是（）

A、植物

B、动物

C、蓝藻

D、真菌

引起中毒的原因及其症状。