It may seem easy to say that plants and animals are different. Any child can tell the difference between  a tree and a dog. But those differences are far deeper than just what they look like. The cells (细胞) that plants are made up of are different. In other words, the cell wall of plants has something special.

First of all, it's important to find that not all plant cells have a cell wall. Besides, there are many differences of a cell wall based on the kinds of plant. The following is meant to be what a plant cell wall is  like.

  The cell wall of a plant is on the outside of the cell membrane (膜). It is usually hard and cannot be bent easily, but the degree of flexibility (韧性) of the cell wall is different. It is based on the special use that the cell has in keeping the plant alive. Cells that make up the trunk of a tree are clearly less flexible than? cells on a leaf.

     Cell walls act in many ways. They serve to protect the plant. They provide support, as well as help in the movement of chemicals and wastes into and out of the cell.  More importantly, they control the water? that goes in and out.  Plants must have good water controlling systems (系统), allowing them to keep water during dry seasons, and get rid of unnecessary water. Plants can't walk around to find water, so  being able to control water is very important.

So there you have it , what a plant cell wall is. Of course, there are many other things that are not talked about here. Knowing more about plant cell wails requires further study and research.

1.From the first two paragraphs we can find that _____.

A. all plants have a ceil wall?????????????

B. plant cells and animal cells are the same

C. different kinds of plant have different cell walls

D. there are no differences between the cells of a tree and a dog

2.The underlined word "bent" in the passage is the closest in meaning to _____.

A. 变形的 ?? B. 防水的   ? C. 太阳灼伤的     ??? D. 表皮破损的

3.Cells in the trunk of a tree are _____ those on a leaf.

A. as flexible as             ?????????  B. not so flexible as

C. more important than                ?? D. less important than

4.What is the most important use of a plant cell wall?

A. To protect the plant.                ???? B. To provide support.

C. To move chemicals and wastes.       D. To control the water.

When you visit Taiwan，Green Island is a wonderful place not to be missed.

Green Island，with clear blue water around it，is an island in the Pacific Ocean,33 kilometers east of Taitung. The old name for Green Island was Huoshandao，meaning “fireburning island”. The island got its name because people on the island used to set up fires at night to help people who went fishing home. Another story goes that in the Qing Dynasty there was a fire and most of the island’s trees and grass died. The coastline(海岸) of the island is only 20 kilometers long，the tallest mountain is only 281 meters high and the island is only 15 km²，but it is attracting(吸引) a growing number of tourists.

Green Island has a lot of interests that make it a place where people like to go：seaside，a clean white beach，green grasslands，seawater，hot springs，beautiful undersea sights，and a great many plants and animals. Another thing of Green Island that people are interested in is its rocks in different shapes. “Sleeping Beauty” and “Pekinese Dog” are the two most strangely shaped ones. There are also other interests which one cannot miss. The green hills，blue sea，clear sky，and ocean gentle winds make a “must” for you.

1.From the article we know Green Island is ________.

A. very large                            B. 281 meters long

C. in the Indian Ocean                   D. 33 kilometers from Taitung

2.According to the two stories，people on Green Island used to ________.

A. meet a lot of visitors                B. set fires to get warm

C. make a living by fishing              D. cut down too many trees and grass

3. The sight “Pekinese Dog” is ________ on Green Island.

A. a cute living dog                     B. a rock like a dog

C. a dog­shaped plant                    D. a dog of “Sleeping Beauty”

4.The last passage is mainly about the ________ of Green Island.

A. sights         B. history       C. people        D. culture