2023年6月英语六级考试立刻就要到来了，想要顺利的通过六级考试，要对每一个题型有一个全方位的认知。其中阅读是最应该要得到提高的。今天@沪江英语四六级公众号为大伙整理2023年6月英语六级阅读理解模拟考试真题： 生物常识，一块儿看一下吧。
2023年6月英语六级阅读理解模拟考试真题： 生物常识
If you go down to the woods today, you may meet high-tech trees genetically modified to speed their growthor improve the quality of their wood. Genetically-engineered food crops have become increasingly common, albeit controversial. over the past ten years. But genetic engineering of trees has lagged behind.
Part of the reason is technical. Understanding. and then altering, the genes of a big pine tree are more complex than creating a better tomato. While tomatoes sprout happily, and rapidly, in the laboratory, growing a whole tree from a single, genetically altered cell in a test tube is a tricky process that takes years, not months. Moreover. little is known about tree genes. Some trees, such as pine trees. have a lot of DNA-roughly ten times as much as human. And, whereas the Human Genome Project is more than half-way throughits task of isolating and sequencing the estimated 100,00 genes in human cells. similar efforts to analyzetree genes are still just saplings .
Given the large number of tree genes and the little that is known about them, tree engineers are starting with a search for genetic "markers". The first step is to isolate DNA from trees with desirable propertiessuch as insect resistance. The next step is to find stretches of DNA that show the presence of a particular gene. Then, when you mate two trees with different desirable properties, it is simple to check which offspring contain them all by looking for the genetic markers. Henry Amerson, at North Carolina State University, is using genetic markers to breed fungal resistance into southern pines. Billions of these are grown across America for pulp and paper, and outbreaks of disease are expensive. But not all individual trees are susceptible. Dr. Amerson’s group has found markers that distinguish fungus-resistant stock from disease-prone trees.Using traditional breeding techniques, they are introducing the resistance genes into pines on test sites in America.
Using generic markers speeds up old-fashioned breeding methods becauseyou no longer have to wait for the tree to grow up to see if it has the desiredtraits. But it is more a sophisticated form of selective breeding. Now. st in genetic tinkering is also gaining ground. To this end, Dr.Amerson and his colleagues are taking part in the Pine Gene Discovery Project. an initiative to identify and sequence the 50,000-odd genes in the pine tree's genome. Knowing which gene does what should make it easier to know what to alter.
1. Compared with genetic engineering of food crops, genetic engineering of trees____________________.
A) began much later
B) has developed more slowly
C) is less useful
D) was less controversial
2. What does the author think about the genetic engineering of pine trees?
A) Time-consuming.
B) Worthwhile.
C) Significant.
D) Technically impossible.
3. What can we learn about the research on tree genes?
A) The research methods are the same as the analysis of human genes.
B) The findings are expected to be as fruitful as the analysis of human genes.
C) It will take as much time and effort as the analyst, of human genes.
D) The research has been mainly concentrated on the genes of young trees.
4. It is discovered by Henry Amerson’s team that_______________.
A) southern pines cannot resist fungus
B) all southern pines are not susceptible
C) the genetic marker in southern pines was the easiest to identify
D) fungus-resistant genes came originally from outside the U.S.A.
5. What is the primary objective of carrying out the Pine Gene Discovery Project?
A) To speed up old-Fashioned breeding methods.
B) To identify all the genes in the pine tree's genome.
C) To find out what desired traits the pine trees have.
D) To make it easier to know which gene needs altering.
答案：
1.相较于粮食作物的基因工程，树木的基因工程______________。
A)开始得较晚
B)进步得较慢
C)用处较小
D)争议性较低
[B]本文并没提到树木基因改良技术从什么时间开始，所以大概树木的基因改良技术和别的基因改良技术在开始的时间上相差不大，但在所获得的成就方面却有非常大的差别，因此，本题重点在于理解首段末句中的lag behind指的是程度上的落后，而非时间上的落后，故B正确。
2.作者对于松树基因工程如何看?
A)耗时。
B)十分值得。
C)非常重要。
D)技术上不可能。
[B]第2段第3句中的that takes years表明研究树木的基因改造技术将花费很久，因此选项A为本题答案。原文没就选项B和C两方面做出讨论，因此不可以判断出这两个选项;虽然第2段首句提到technical一词，但文章表明树木基因改造技术是可行的。只不过会花费较多的时问，因此选项D也不正确。
3.对于树木基因进行的研究，大家获悉什么?
A)研究办法与剖析人类基因时相同。
B)大家预计研究成就会与人类基因剖析一样硕果累累。
C)所花的时间和精力与人类基因剖析一样多。
D)研究主要关注在小树的基因上面。
[A]第2段末句中的similar cfforts指的就是task of isolating and sequencing，即剖析基因的常用办法。该句表明人类基因和树种基因的剖析办法相同，但进展有差别，因此选项A为正确的判断。
4.Henry Amerson的研究小组发现，__________________。
A)南部黄松不可以抵抗真菌
B)并非所有些南部黄松都比较容易染病
C)南部黄松的基因标记最易辨别
D)有真菌抵抗能力基因来源于海外而非美国
[B]选项B是一个半否定的句式，因此本题重点在于理解选项B的Al1...are not...结构在乎义上等同于第3段倒数第3句的not all... are...。第3段倒数第2句中的fungus-resistant stock指的是南方松树中能抗真菌的树种，并不是别的与南方松树毫不有关的树种，因此A的说法不正确。
5.拓展“松树基因发现项目”的主要为了什么?
A)加快旧式的育种办法。
B)辨别松树基因组中的所有基因。
C)找到松树所具备的优质特征。
D)让发现什么基因需要做改变的过程变得愈加简单。
[B]末段倒数第2句中的an initiative...是the Pine Gene Discovery Project的同位语，表明拓展该计划的目的，因此选项B为本题答案。其他选项都是在完成该计划后可以达成的工作，它们都要以松树基因的排列组合为基础，因此，这类选项都不是primary objective，而是在达成了primary objective之后继续进行的工作。
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