第3部分：概括大意与完成句子（第23~30题，每题1分，共8分）

下面的短文后有2项测试任务：（1）第23~26题要求从所给的6个选项中为第2~5段每段选择1个最佳标题；（2）第27~30题要求从所给的6个选项中为每个句子确定1个最佳选项。　

Unlocking the Human Genome（基因组）

1　A project to unlock secrets-what scientist could resist that challenge?This is what many scientists are doing as they work on the Human Genome Project.The aim of the project is to decode（破译）all of the some 100,000 genes in the human body.Scientists are using DNA fingerprinting techniques to do the decoding.

2　DNA is the substance found in the chromosomes（染色体）of a cell.A chromosome is a chain of genes.Each gene carries a piece of genetic information.At any one moment in a cell,thousands of genes are turned on and off to produce proteins（蛋白质）.The challenge for scientists is to find out what role each gene plays in protein production.At some point this decoding will be complete.Then scientists will have a map of an ideal genome,or a picture of the total genetic nature of a human being.The ideal genome is called a consensus（交感）genome.Everything works well in a consensus genome.
3　But no one in the world has a consensus genome.Everyone's genome is different from the ideal.These differences are referred to as genetic mutations（突变）.Genetic mutations in a person's genome mean that the person has a greater than average chance of suffering from health problems.Some problems are not life-threatening.These would include things like colorblindness,or mild headaches.Other problems are serious,such as heart disease,or cancer.
4　It will take years to identify the role of each of the 100,000 genes,The short-term goal of the project is to find the physical and mental health problems a person is likely to encounter during his or her lifetime.The long-term goal is to have each person live a longer,healthier life.

23.paragraph 1　.
24.paragraph 2　.
25.paragraph 3　.
26.paragraph 4　.
A　How does DNA work?
B　What is the Human Genome Project about?
C　How are the DNA samples collected?
D　What are the goals of the Human Genome Project?
E　What is the role of each gene?
F　What are the consequences of genetic mutations?

27.The Human Genome Project is trying to map allthat make us human.
28.Decoding the human  genome is a challenge to.
29.Genetic mutations in a person's genome may affect.
30.Scientists are trying hard to discoverof each of the genes in our body.
A　that person's health
B　a scientific answer
C　scientfic researchers
D　the genes
E　the function
F　the size

答案:   23.B　24.E　25.F　26.D　27.D　28.C　29.A　30.E