Question

    Why is it that you can remember the name of your childhood best friend that you haven't seen in years yet easily forget the name of a person you just met a moment ago？In other words, why are some memories stable over decades, while others disappear within minutes？

Caltech researchers carried out their work about memories in the laboratory. The research team developed a test to examine mice's neural（神经的）activity as they learn about and remember a new place. In the test, a mouse was placed in a straight enclosure( 围 场 ), about 5 feet long with white walls. Unique symbols marked different locations along the walls. Sugar water（a treat for mice）was placed at either end of the track.

When a mouse was placed in the track, it was unsure of what to do at first and wandered left and right until it came across the sugar water. In these cases, single neurons were activated when the mouse took notice of a symbol on the wall. Over numerous experiences with the track, the mouse became familiar with it and remembered the locations of the sugar water. As the mouse became more familiar, more and more neurons were activated when seeing each symbol on the wall. Essentially, the mouse was recognizing where it was with respect to each unique symbol.

To study how memories disappear over time, the researchers then kept back the mice from the track for up to 20 days. Upon returning to the track after this break, mice that had formed strong memories encoded（编码）by higher numbers of neurons remembered the task quickly. Even though some neurons showed different activity, the mouse's memory of the track was clearly identifiable when researchers analyzed the activity of large groups of neurons.

This work shows that memories might disappear more rapidly as we age because a memory is encoded by fewer neurons, and if any of these neurons fail, the memory will be lost. The study suggests that one day, designing treatments that could encourage a higher number of neurons to encode a memory could help prevent memory loss.

1.What is the purpose of the first paragraph?

A.To introduce the topic of the text.

B.To show the examples of bad memory.

C.To compare different people's memories.

D.To prove the importance of childhood memories.

2.During the research, the mouse _______

A.lost interest in the symbols soon

B.had to climb over the long white wall

C.would get sugar water as their rewards

D.wandered left and right nervously all the time

3.What is special about the mice that remembered the task quickly after the break?

A.They had their neurons show different activity.

B.They love sugar water better than other mice.

C.They stayed in the track for over 20 days.

D.They possessed more activated neurons.

4.What does the last paragraph imply?

A.Mice's memory seems better than humans

B.The aging process of humans is unavoidable.

C.Memory loss is expected to be cured in the future.

D.The study has found the way to prevent neurons from failing.

Answer

1.A

2.C

3.D

4.C

【解析】

这是一篇科普说明文。文章通过老鼠的试验，来说明记忆的丧失。记忆丧失有望在未来得到治愈。

1.推理判断题。根据第一段Why is it that you can remember the name of your childhood best friend that you haven't seen in years yet easily forget the name of a person you just met a moment ago？In other words, why are some memories stable over decades, while others disappear within minutes？“为什么你能记住多年未见的儿时好友的名字，却很容易忘记刚刚认识的人的名字?换句话说，为什么有些记忆几十年不变，而有些却在几分钟内就消失了?”由此可知，第一段的目的是为了引出文章的主题。故选A。

2.推理判断题。根据第三段中Over numerous experiences with the track, the mouse became familiar with it and remembered the locations of the sugar water.“在无数次使用这条轨迹的经历中，老鼠逐渐熟悉了它，并记住了糖水的位置。”由此可知，在研究过程中，老鼠会得到糖水作为奖励。故选C。

3.推理判断题。根据第四段中Upon returning to the track after this break, mice that had formed strong memories encoded（编码）by higher numbers of neurons remembered the task quickly.“在这一休息之后回到轨道上时，那些已经形成了由更多的神经元编码的强大记忆的老鼠很快就记住了这个任务。”由此可知，休息后很快记住任务的老鼠的特殊之处是“他们拥有更多被激活的神经元。”故选D。

4.推理判断题。根据最后一段中This work shows that memories might disappear more rapidly as we age because a memory is encoded by fewer neurons, and if any of these neurons fail, the memory will be lost. The study suggests that one day, designing treatments that could encourage a higher number of neurons to encode a memory could help prevent memory loss.“这项研究表明，随着我们年龄的增长，记忆可能会消失得更快，因为记忆是由更少的神经元编码的，如果这些神经元中的任何一个消失了，记忆就会消失。这项研究表明，有朝一日，设计出一种能够促使更多神经元编码记忆的治疗方法，可能有助于防止记忆丧失。”由此可知，最后一段暗示我们“记忆丧失有望在未来得到治愈。”故选C。