问题 解答题

图为某植物茎的结构示意图,请根据该示意图回答下列有关问题:

(1)图中[1]所在位置主要含有起运输功能的结构是______,运输的物质是______;图中[3]所在的位置起运输功能的结构是______,运输的物质是______.

(2)图中[2]所示结构为______,其特点是能够进行______.因为有了这一结构,所以该植物茎能够______.

答案

木本植物茎的结构有木质部、形成层、韧皮部三部分.图中1是木质部;2是形成层;3是韧皮部.

(1)图中1为木质部,内有导管,导管有运输作用,可以从下往上运输水分和无机盐.图中3为韧皮部,内有筛管,筛管具有运输功能,可以把植物体通过光合作用制造的有机物从上往下运输到茎、根等部位.

(2)图中2为形成层.形成层的细胞不断地分裂增生,其中,大部分细胞向内形成木质部,少量细胞向外形成韧皮部,从而使得树干不断地加粗.

故答案为:(1)导管; 水和无机盐;筛管; 有机物

(2)形成层; 分裂; 逐渐增粗

阅读理解

阅读理解。

     We are all busy talking about and using the Internet, but how many of us know the history of the

Internet?

     Many people are surprised when they find that the Internet was set up in the 1960s. At that time ,

computers were large and expensive. Computer networks(网络) didn't work well. If one computer

in the networks broke down, then the whole network stopped. So a new network system (系统) had

to be set up. It should be good enough to be used by many different computers. If part of the network

was not working, information(信息)could be sent through another part. In this way computer network

system would keep on working all the time.

     At first,the Internet was only used by the goverment(政府),but,in the early 1970s, university(大学),

hospitals and banks were allowed ( ) to use it too. Howerver,computers were still expensive and the

Internet was difficult to become cheaper and easier to use. Scientists had also developed software(软件)

that made "Surfing"(浏览)the Internet more convenient(方便). 

     Today it is easy to get-on-line and it is said that millions of people use the internet every day. Sending e-mail is more and more popular among students.

     The Internet has now become one of the most important parts of people's life.

1.The Internet has a history of ______ years.

A.about 40

B.less than 30

C.more than 45

D.nearly 35

2.Scientists set up a new network system to _______.

A. make the computer cheaper.

B.use the computer widely

C.make the computer go well

D.develop new softwares

3.The Internet was widely used in the _______.

A.1960s

B.1970s

C.1980s

D.1990s

4.The underlined words "get-on-line" in Chinese means "_______"

A.上机

B.上网

C.接线

D.买电脑

5.Which of the following is NOT ture?

A.In the 1960s computer networks system went wrong easily.

B.Computers are much cheaper than before.

C.Today the Internet is used everywhere.

D.People had enough softwares to get on-line fifteen years ago

选择题