Motherhood may make women smarter and may help prevent dementia(痴呆) in old age by bathing the brain in protective hormones(荷尔蒙) , U.S. researchers reported on Thursday.

Tests on rats show that those who raise two or more litters of pups do considerably better in tests of memory and skills than rats who have no babies, and their brains show changes that suggest they may be protected against diseases such as Alzheimer’s(早老痴呆症). University of Richmond psychology professor Craig Kinsley believes his findings will translate into humans.

“It’s rat data but humans are mammals just like these animals are mammals,” he added in a telephone interview. “They go through pregnancy and hormonal changes.”

Kinsley said he hoped public health officials and researchers will look to see if having had children protects a woman from Alzheimer’s and other forms of age-related brain decline.

“When people think about pregnancy, they think about what happens to babies and the mother from the neck down,” said Kinsley, who presented his findings to the annual meeting of the Society of Neuroscience in Orlando, Florida.

“They do not realize that hormones are washing on the brain. If you look at female animals who have never gone through pregnancy, they act differently toward young. But if she goes through pregnancy, she will sacrifice her life for her infant—that is a great change in her behavior that showed in genetic alterations(改变) to the brain.”

4. How do scientists know “Motherhood may make women smarter”?

A. Some researchers have told them.

B. Many women say so.

C. They know it by experimenting on rats.

D. They know it through their own experience.

5. What does the phrase “litters of pups” mean in the second paragraph?

A. Baby rats. B. Animals. C. Old rats. D. Grown-up rats.

6. What can protect the brain of a woman according to the passage?

A. Estrogen. B. The hormones of pregnancy.

C. More exercise. D. Taking care of children.

7. “It’s rat data but humans are mammals just like these animals are mammals.” What does the sentence suggest?

A. The experiments on the rats have nothing to do with humans.

B. The experiments on the rats are very important for animals.

C. The experiments on the rats are much the same on humans.

D. The experiments on the rats are much the same on other animals.

8. Which title is the best for this passage?

A. Do You Want to Be Smarter?

B. Motherhood Makes Women Smarter

C. Mysterious Hormones

D. An Important Study

本文介绍了一个观点：母性特点能使妇女变得更加聪明灵敏。

4. C。细节题。根据Tests on rats show… 可知科学家是通过做老鼠实验得出这个结论的。

5. A。词义猜测题。后面的对比who have no babies，实际上提供了一个相反的情况，所以我们可以推测those who raise two or more litters of pups中的litters of pups指的是“刚出生不久的小老鼠”。

6. B。细节题。根据文章第 3 段中的 …the hormones of pregnancy(怀孕) are protecting the brain可得出答案。

7. C。句意理解题。科学家通过用老鼠做实验来说明人的问题。因为人和老鼠都属于哺乳动物，很多生理机能都相同。

8. B。主旨题。短文第 1 句 Motherhood may make women smarter 是主题句，据此我们可以得出答案。