客运杂费收据的保管期限为（）。A.3年 B.5年 C.10年 D.15年

一列火车每小时行驶110千米，飞机每小时飞行的速度比火车速度的8倍少20千米．飞机每小时飞行的速度是多少千米？

竞技促销策略是指利用消费者之间的竞争，通过消费者切身参与，展示其才华、技能以达到扩大产品影响力，最终达到促进产品销售的目的。 根据定义，下列属于竞技促销策略的是( )。

A．百威啤酒开展的喝百威啤酒比赛，向胜出者发放10箱啤酒

B．某健身器械商邀请健身教练来做示范，顾客也可以有半小时的免费体验

C．某电器经销商举行抽奖活动，凡是购买一款冰箱的，都能抽到奖品

D．某品牌手机赞助该市的运动会，凡是冠军都将得到一款该品牌的手机

铬引起的癌多为（）

A.鳞癌

B.腺癌

C.扁平细胞角化癌

D.基底细胞癌

E.未分化小细胞癌

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.

A good title for this passage would be ______.

A．the Arctic Summer

B．Marmots and Squirrels

C．Keeping Warm in the Arctic

D．Freezing Temperatures

脾脏的阳气损伤，是内寒病理产生的主要病理基础。