问题 单项选择题

基因诊断和基因治疗中争论最激烈的伦理难题是

A.胎儿的生命质量和父母选择权的矛盾

B.人类遗传物质的纯洁性、神圣性是否受到了亵渎

C.对个体和人类社会是否安全

D.是否会造成医疗费用的猛增

E.生殖细胞的基因治疗是否可行

答案

参考答案:E

选择题
阅读理解

阅读理解

     Trees are useful to man in three important ways: they give him wood and other useful things, they give

him cool places, and they help to stop drought and flood.

     Unluckily, in many parts of the world, man has not found that the third of these points is the most

important. Man wants to make money from trees, so he has cut them down in large numbers, only to find

that without them he has lost the best friends he had. And also, he is usually too careless to plant and look after new trees. So the forests slowly disappear.

     This does not only mean that man will have fewer trees. The results are even worse: for where there are trees, their roots break up soil, make the rain in, and also bind the soil, thus stopping it from being washed away easily; but where there are no trees, the rain falls on hard ground and flows away, causing floods and carrying away the rich top-soil. When all the top-soil is gone, nothing is left but useless desert.

1. The most important points of trees to man is ________.

A. they help him to make money            

B. they give him cool

C. they give him wood and other things      

D. they help him to stop drought and floods

2. In many places forests slowly disappear because ________.

A. many trees have been cut down by man            

B. new trees are not well looked after

C. man has not paid enough attention to planting trees    

D. all the above

3. Land becomes desert after all trees are cut down because ________.

A. roots of trees break up the soil      

B. there are too many rainfalls to make it

C. strong winds bring a lot of sand      

D. no tree keeps the rain and protects the top-soil.

4. Which title best fits the passage?

A. Trees and Man                        

B. The Function of Tree Wood

C. How do People do with Trees?            

D. The Usage of Tree Roots