Question

    A freshly baked roll is as delightful as a soft，light cloud on a summer's day.What gives bread much of its appealing texture is gluten，a group of proteins found in wheat.But in people with celiac disease(乳糜泻)，gluten damages the small intestine(肠).Many others may have milder gluten intolerance and avoid foods that contain it.

Most gluten-free bread is made from alternative flours such as rice or potato，so it tastes and feels different from wheat bread.Now，however，researchers say that they have found a way to genetically engineer wheat that contains far less of the most troublesome type of gluten—but still has other proteins that give bread its characteristic taste and springiness.

Genetically modified crops are the subject of fierce debate around the world.The biggest concern involves the practice of inserting DNA from one species into another，says Francisco Barro，a plant biotechnologist.To avoid this genetic crossover，Barro and his colleagues used the gene-editing technique CRISPR／Cas9 to cut selected genes from a wheat genome(基因组).

Their study zeroed in on alpha-gliadins(α-胶质蛋白)，gluten proteins believed to be wheat’s major troublemakers in the immune system.The researchers designed bits of genetic material that directed the scissor-like Cas9 protein to cut out 35 of the 45 alpha—gliadin genes.When the modified wheat was tested in a Petri dish，it produced an 85 percent weaker immune response，the team reported online last September in Plant Biotechnology Journal.

Wendy Harwood，a crop geneticist at the John Innes Center in England，who was not part of the study，notes that the engineered wheat has a long way to go before it can be turned into anything marketable.“I don’t think it's the end of the story.”she says.“This is just a really important step in maybe producing something that is going to be incredibly useful.”To develop a completely safe strain of wheat for celiac patients，the researchers may need to target more of the gluten genes.Barro says his team is working on that.

1.What’s the text mainly about?

A. Making gluten—free bread.

B. Advantages of gluten-free wheat.

C. Debate about genetically modified crops.

D. Developing genetically engineered wheat.

2.Why is bread mentioned in paragraph 1?

A. To advertise a new study.

B. To raise the topic to be written about.

C. To provide some advice for the readers.

D. To popularize some information about medicine.

3.What concerns people most according to paragraph 3?

A. Genetic crossover.    B. Gene-editing technique.

C. The practice of using DNA.    D. The subject of fierce debate.

4.What’s Wendy Harwood’s attitude towards engineered wheat?

A. A little alarmed.    B. Mildly surprised.

C. Somewhat opposed.    D. Cautiously optimistic.

Answer

1. D

2. B

3. A

4. D

【解析】

本文属于科普文，主要介绍小麦中面筋对患有乳糜泻的人有副作用，因此可以利用基因技术来改良小麦中的DNA，减少面筋的含量，但是距离投入市场还有很长的路要走。

1.主旨大意题。根据文章可知，本文主要阐述小麦中面筋对患有乳糜泻的人有副作用，因此可以利用基因技术来改良小麦中的DNA，减少面筋的含量故选D。

2.作者意图题。根据第一段可知，本段提及面包是为了引出面筋的作用，因而属于引出话题，故选B。

3.细节理解题。根据第三段The biggest concern involves the practice of inserting DNA from one species into another，says Francisco Barro，a plant biotechnologist.可知，最大的担忧就是把DNA从一种物种植入到另外一种，故选A。

4.态度观点题。根据最后一段Wendy Harwood，a crop geneticist at the John Innes Center in England，who was not part of the study，notes that the engineered wheat has a long way to go before it can be turned into anything marketable.可知，该基因学家认为基因改良的小麦要投入市场还有很长的路要走，故可知他对此是谨慎又乐观的态度，故选D。