关于“流行病学”，下列说法错误的是（） A.流行病学从疾病分布入手探讨疾病的流行因素

If you are lost in the mountains, stay calm in the face of darkness, loneliness, and the unknown. It will greatly increase your chances of survival. Many people think that preparing necessary equipment and knowing how to use it are very important, but actually eighty percent of mountain survivals is your reaction(反应) to fear.

Find a hiding place.

Unnecessary efforts will make you sweat and make you cold. Find a hiding place around you before trying to start your own construction. If you are in a snow-covered area, you may be able to dig a cave in deep snow for protection from the wind. You should try to hide yourself in the middle of the mountain if possible. Stay out of valleys—cold air falls, and the valley floor can be the coldest area on the mountain.

Signal rescuers for help.

The best time to signal rescuers(救援者) is during the day. Signal for help from the highest point possible—it will be easier for rescuers to see you, and any sound you make will farther. If you take a box of matches and a space blanket (a special blanket for traveling), build three smoky fires and put your blanket—gold side facing out—on the ground.

Do not walk away.

It will make finding you more difficult, as search teams will be trying to follow your path and may miss you if you have gone off in a different direction. Searchers often end up finding a car with no one.

If you get frostbite（冻伤）, do not rewarm the affected area until you’re out of danger. You can walk on frostbitten feet, but once you warm the area and can feel the pain, you will not want to walk anywhere. Try to protect the frostbitten area and keep it dry until you are rescued.

小题1:When lost in the mountains, you can increase your chances of survival if you _____.

A．try to find a car immediately

B．take a space blanket with you

C．do more physical labor

D．walk as far as possible to find help小题2:According to the passage, people most probably fail to survive if they _____.

A．do not keep themselves warm

B．stay in the middle of the mountain

C．do not take enough equipment

D．stay in a snow-covered area小题3:What can we infer from the passage?

A．Never go to unfamiliar places alone.

B．Mountain traveling is dangerous.

C．Don’t get frightened in danger.

D．Don’t travel by yourself.小题4:The passage talks mainly about _____.

A．mountain traveling

B．mountain dangers

C．mountain survivals

D．mountain searching

放电影时银幕上发生的反射属于什么反射？简述银幕做成白色的原因。

进出口商品检验制度

当一个人的语言和非语言行为发生矛盾时，我们更倾向于相信非语言行为，这时因为非语言行为具备以下哪项特点

A．多渠道
B．多功能
C．真实性
D．情绪表现
E．多种含义

某酸在18℃时的平衡常数为1.84×10^－5，在25℃时的平衡常数为1.87×10^－5，则说明该酸（）。

A.在18℃时溶解度比25℃时小

B.的电离是一个吸热过程

C.温度高时电离度变小

D.温度高时溶液中的氢离子浓度变小