Question

    They still bite, but new research shows lab-grown mosquitoes are fighting dengue fever — a dangerous disease that they normally would spread. Dengue infections appear to be dropping fast in communities in Indonesia, Vietnam, Brazil and Australia that are filled with the specially grown mosquitoes.

Researchers first injected （注射）mosquito eggs with Wolbachia bacteria that's common in insects and harmless to people in a lab. Infected females then pass the bacteria on through their eggs. Releasing enough Wolbachia carriers, both the females that bite and the males that don't, allows mating（交配）to spread the bacteria through a local mosquito population.

Rather than using chemicals to wipe out pests, “this is really about transforming the mosquito," said Cameron Simmons of the nonprofit World Mosquito Program, which is conducting the research.

The first success came from Australia. Mosquitoes carrying Wolbachia were released in parts of North Queensland starting in 2011, and gradually spread through the local mosquito population. Dengue is spread when a mosquito bites someone who is infected, and then bites another person, but somehow Wolbachia blocks that — and local spread has nearly disappeared in those North Queensland Communities, Simmons said.

The studies are continuing in other countries. But the findings, presented at a meeting of the American Society for Tropical Medicine and Hygiene, suggest it's possible to turn at least some mosquitoes from a public health threat into annoying biters.

The work marks “exciting progress," said Michigan State University professor Zhiyong Xi, who wasn't involved with the project but has long studied how Wolbachia can turn mosquitoes against themselves.

More research is needed, specialists cautioned. "The results are pretty exciting — strong levels of reductions — but there clearly are going to be things to be learned from the areas where the reductions are not as great," said Penn State University professor Elizabeth McGraw.

1.What can we learn about the lab-grown mosquitoes?

A.They lose the ability to bite people.

B.They become harmful to human beings.

C.They carry dangerous Wolbachia bacteria.

D.They spread Wolbachia bacteria by mating.

2.What does the underlined word "that" refer to in Paragraph 4?

A.The bite from a mosquito. B.The local community.

C.The spread of Dengue. D.The infected person.

3.What do the last two paragraphs suggest?

A.This research proves a complete success.

B.Scientists agree on this research.

C.There is still room for improvement.

D.Mosquitoes turn themselves against harmful ones.

4.What is the best title for the text?

A.Bacteria- infected Mosquitoes Bite Deadly Dengue.

B.Transform Mosquitoes into Annoying Biters

C.Fight against Mosquitoes with Wolbachia

D.Harmless Mosquitoes Are on Their Way

Answer

1.D

2.C

3.C

4.A

【解析】

本文为一篇说明文。文章讲述了研究人员实验室培育的蚊子抗击登革热病毒的事例。

1.细节理解题。根据第二段“Releasing enough Wolbachia carriers, both the females that bite and the males that don't, allows mating（交配）to spread the bacteria through a local mosquito population.” 释放出足够的携带Wolbachia的蚊子，会通过交配传播Wolbachia。即实验室培育的蚊子通过交配传播Wolbachia菌。故选D项。

2.词句猜测题。根据第四段“Dengue is spread when a mosquito bites someone who is infected, and then bites another person, but somehow Wolbachia blocks that — and local spread has nearly disappeared in those North Queensland Communities, Simmons said.”可知，登革热病毒通过叮咬的方式传染，但携带Wolbachia的蚊子与此不同，所以that指登革热病毒的传播。故选C项。

3.细节理解题。根据第七段“The results are pretty exciting — strong levels of reductions — but there clearly are going to be things to be learned from the areas where the reductions are not as great”可知我们仍然需要从削减领域不够的地方学习，还有改进的余地。故选C项。

4.主旨大意题。由文章开头“They still bite, but new research shows lab-grown mosquitoes are fighting dengue fever”可知本文讲的就是实验室培育的蚊子抵御登革热病毒，A项“感染细菌的蚊子抗击致命的登革热。”符合文章主旨。故选A项。