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.

Success is not easy to talk about because for some people it means power, for some people it means wealth(财富), for others it is fame(名声) or great achievements. But I have my own understanding of it. Here are some my different ways to succeed.

Success means to try your best. Many people believe that success means to win. In my opinion, it means to try your best when you do everything, no matter you will win or not. When you are taking part in a long-distance race, if you keep on running as fast as you can, you are

①       , although you may be the       to pass the finishing-line.

Success means to work hard. No one can be successful without any hard work. Tomas Edison succeeded, because he had experimented thousands of times to find the best material for lights. Every success calls for hard work.

Success means not to lose heart. No one can always be the winner. You will certainly lose or fail some day. It is important for you not to lose heart. Nobel had failed many times when he was doing his experiments. Sometimes his lab was on fire and he was nearly killed. But he never lost heart and kept on trying. Finally he invented a new explosive（炸药）. ② So when you fail or meet any difficulty, just believe in yourself, stand up and give the difficulty a heavy strike.

76. 在①处填上适当词使文章完整。___________　___________

77. 将②处译成汉语。

______________________________________________________________

78. What is success according to the understanding of it ?

_____________________________________________________________________________

79. 找出与下列句子意思相同的句子。

Anybody won’t be successful unless they work hard.

_____________________________________________________________________________

80. 找出本文的主题句。

 Success is not easy to talk about because for some people it means power, for some people it means wealth(财富), for others it is fame(名声) or great achievements. But I have my own understanding of it. Here are some my different ways to succeed.

Success means to try your best. Many people believe that success means to win. In my opinion, it means to try your best when you do everything, no matter you will win or not. When you are taking part in a long-distance race, if you keep on running as fast as you can, you are

①       , although you may be the       to pass the finishing-line.

Success means to work hard. No one can be successful without any hard work. Tomas Edison succeeded, because he had experimented thousands of times to find the best material for lights. Every success calls for hard work.

Success means not to lose heart. No one can always be the winner. You will certainly lose or fail some day. It is important for you not to lose heart. Nobel had failed many times when he was doing his experiments. Sometimes his lab was on fire and he was nearly killed. But he never lost heart and kept on trying. Finally he invented a new explosive（炸药）. ② So when you fail or meet any difficulty, just believe in yourself, stand up and give the difficulty a heavy strike.

76. 在①处填上适当词使文章完整。___________　___________

77. 将②处译成汉语。

______________________________________________________________

78. What is success according to the understanding of it ?

_____________________________________________________________________________

79. 找出与下列句子意思相同的句子。

Anybody won’t be successful unless they work hard.

_____________________________________________________________________________

80. 找出本文的主题句。