题目内容：

    Drug companies have spent billions of dollars searching for therapies to reverse or significantly slow Alzheimer’s disease, but in vain. Some researchers argue that the best way to make progress is to create better animal models for research, and several teams are now developing mice that more closely imitate how the disease destroys people’s brains.

The US National Institutes of Health (NIH), the UK Dementia Research Institute and Jackson Laboratory (JAX) - one of the world’s biggest suppliers of lab mice - are among the groups trying to genetically design more suitable mice. Scientists are also exploring the complex web of mutations(突变) that influences neurological(神经学的) decline in mice and people.

“We appreciate that the models we had were insufficient. I think it’s sort of at a critical moment right now.” says Bruce Lamb, a neuro-scientist at Indiana University who directs the NIH-funded programme.

Alzheimer’s is marked by cognitive impairment(认知损伤) and the build-up of amyloid-protein plaques(淀粉样蛋白块) in the brains of people, but the disease does not occur naturally in mice. Scientists get around this by studying mice that have been genetically modified to produce high levels of human amyloid protein. These mice develop plaques in their brains, but they still do not display the memory problems seen in people.

Many experimental drugs that have successfully removed plaques from mouse brains have not lessened the symptoms of Alzheimer’s disease in people. One focused stumble came last month, when three companies reported that their Alzheimer’s drugs had failed in large, late-stage clinical trials. Although the drugs successfully blocked the accumulation of amyloid protein in mice, they seemed to worsen cognitive decline and brain shrinkage in people.

The drive for better mouse models comes as genomics studies are linking the most common form of Alzheimer’s to dozens of different genes. This diversity suggests that each case of the disease is caused by a different combination of genetic and environmental factors. “There is no single Alzheimer’s disease,” says Gareth Howell, a neuro-scientist at Jackson Laboratory (JAX) in Bar Harbor, Maine.

Howell argues that scientists’ reliance on lab mice with only a few genetically engineered mutations might have limited research. His own work suggests that in mice, just as in people, genetic diversity plays a part in determining how Alzheimer’s develops.

1.What do you know about the lab mice used for the Alzheimer’s research from the text?

A.The lab mice also display the memory problems.

B.Suitable lab mice are fundamental to the research.

C.Mice with Alzheimer’s disease suffer from mutations.

D.Drugs have been invented to slow Alzheimer’s disease.

2.From paragraph 5, we can know that the experimental drugs “__________”.

A.functioned well in large, early-stage clinical trials

B.fail to make people get rid of the relevant symptoms

C.successfully prevent people forming amyloid protein

D.worsen cognitive decline and brain shrinkage in mice

3.What does Gareth Howell think of Alzheimer’s?

A.It is various genes that count in the development of Alzheimer’s.

B.The increasingly polluted environment contributes to Alzheimer’s.

C.The most common form of Alzheimer’s is the drive for better mice.

D.It is caused by the accumulation of amyloid-protein plaques in people.

4.Which of the following could be the best title for the passage?

A.Experimental drugs successfully reverse Alzheimer’s

B.The real causes of Alzheimer’s have been confirmed

C.Alzheimer’s is the biggest memory killer in the aged

D.Frustrated Alzheimer’s researchers seek better lab mice