问题 选择题

蜂蜜总含糖量达65%-75%,还含有丰富的酶类,水溶性维生素及钙、铁、锌等。新鲜的蜂蜜可直接食用,也可配成水溶液,但不可用开水或高温蒸煮。下列说法正确的是

A.钙、铁、锌是人体必需的微量元素

B.高温会使酶活性增强

C.蜂蜜属于混合物,主要成分是糖类

D.开水使蜂蜜结晶析出

答案

答案:C

题目分析:A 人体的常量元素有C、H、O、N、P、S、K、Ca、Mg等,钙元素属于人体必需的常量元素;B 酶主要由蛋白质组成,高温会使其变性失去活性;C蜂蜜总含糖量达65%-75%,所以蜂蜜属于混合物,主要成分是糖类;D 低温或者失去水分可以使蜂蜜中的糖类物质结晶析出,开水可以使蜂蜜融化。

点评:考察生活中常见现象里的化学知识,较简单,但是却是中考中的必考题,平时注意积累总结。

填空题
阅读理解

阅读理解。

      At one time, computers were expected largely to remove the need for paper copies of

documents because they could be stored electronically. But for all the texts that are written,

stored and sent electronically, a lot of them are still ending up on paper.

      It is difficult to measure the quantity of paper used as a result of use of Internet-connected

computers, although just about anyone who works in an office can tell you that when e-mail is

introduced, the printers start working overtime. "I feel in my bones this revolution is causing

more trees to be cut down," says Ted Smith of the Earth Village Organization.

      Perhaps the best sign of how computer and Internet use pushes up demand for paper

comes from the high-tech industry itself, which sees printing as one of its most promising new

markets. Several Internet companies have been set up to help small businesses print quality

documents from a computer. Earlier this week Hewlett-Packard Co. announced a plan to

develop new technologies that will enable people to print even more so they can get a hard

copy of a business document, a medical record or just a one-line e-mail, even if they are

nowhere near a computer. As the company sees it, the more use of the Internet the greater

demand for printers.

     Does all this mean environmental concerns have been forgotten? Some activists suggest

people have been led to believe that a lot of dangers to the environment have gone away.

"I guess people believe that the problem is taken care of, because of recycling," said Kelly

Quirke, director of the Rainforest Action Network in San Francisco. Yet Quirke is hopeful

that high-tech may also prove helpful. He says printers that print on both sides are growing

in popularity. The action group has also found acceptable paper made from materials other

than wood, such as agricultural waste.

1.The growing demand for paper in recent years is largely due to ____.

A.the rapid development of small businesses  

B. the opening up of new markets

C. the printing of high quality copies          

D. the increased use of the Internet

2.  Environmentalists believe one possible way of dealing with the paper situation is ____.

A.to encourage printing more quality documents

B.to develop new printers using recycled paper

C.to find new materials for making paper

D.to plant more fast-growing trees

3.Hewlett-Packard Co. has decided to develop new technologies because ____.

A.people are concerned about the environment

B.printers in many offices are working overtime

C.small companies need more hard copies

D.they see a growing market for printers

4.What would be the best title for the text?

A.Computers and Printers                

B. E-mail and the Business World

C. Internet Revolution and Environment      

D. Modern Technology and New Markets