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问题 单项选择题

多发性神经纤维瘤病Ⅰ型是指伴有下列特点（）

A.双侧听神经瘤

B.多发性脑膜瘤

C.脊神经鞘瘤

D.皮肤牛奶咖啡斑

E.皮肤多发性瘀斑

答案

参考答案：D

解析：多发性神经纤维瘤病Ⅰ型呈现皮肤牛奶咖啡斑和神经纤维瘤样的肿瘤，多伴有骨骼畸形、智力障碍和虹膜结节等。

判断题

操纵器设计时为减轻人员疲劳，操纵阻力越小越好。
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单项选择题

Imagine going to sleep in October and waking up in May! Well, marmots and ground squirrels stay warm by sleeping all winter. All this time, they do not wake up once. This special kind of sleep is called hibernation. During this sleep, the heart slows down, and the animal breathes more slowly, it doesn’t move around, so it uses less energy.
Animals like the marmot and the ground squirrel inhabit the coldest parts of the world. They need special talents to survive in these frigid places. Their furry coats keep them snug when the temperature falls below zero. It often gets this cold in the Arctic, a land that is just below the North Pole.
Before the long winter, some animals eat and eat. After a while, they grow very fat. When the winter comes, they live on the fat saved up in their bodies. Layers of fat keep an animal warm.
Arctic animals also have other ways to beat the cold. Rabbits in the Arctic, for example, have very small ears. Small ears keep heat in, while big ears let it out. Small things usually keep heat in. Have you ever slept in a room that is very small, and noticed how hot it can get.’
It rarely gets warm in the Arctic. But although summer seasons there are very short, the sun shines brightly. Plants seem to spring up before your eyes! Animals such as caribou look forward all year to summer, when they can eat fresh grass again. Every minute of sunshine is important to their lives.

The way for marmot to keep warm is ______.

A．to be very fat

B．to have small ears

C．to eat green grass

D．to have thick and soft hairs
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