17.Travel is exciting and summer is a busy period for holiday travel.Many people will travel great distances in airplanes,cars or other vehicles.Experts say people should know about other health problems that can strike when traveling by air.
One of these is a condition called hypoxia (缺氧癥).It results from a lack of oxygen to the brain.Experts say the body begins losing oxygen minutes after an airplane leaves the ground.The air pressure in a plane during flight is lower than at sea level.This makes it more difficult for the body to effectively use the same amount of oxygen as it would on the ground.Fewer oxygen molecules (分子) cross the tissues (組織) in the lungs and reach the bloodstream.
The result is a five to twenty percent drop in the amount of oxygen in the blood.This reduces the amount of oxygen that reaches the organs of the body.
One effect of this lack of oxygen to the brain is a headache.When this happens,the heart attempts to fix the situation by beating harder and faster.This can make the traveler feel tired.
These signs of hypoxia are not dangerous in a healthy person.But a drop in oxygen level can cause a health emergency in people with heart or lung problems.They might lose consciousness or even suffer a heart attack.
Experts say that smoking cigarettes and drinking alcoholic liquids also reduce the body's ability to use oxygen.So they suggest that people not drink alcohol or smoke cigarettes either before or during a flight.They also say persons with heart or lung problems should seek advice from their doctors before flying.
63.The author writes the passage mainly toC.
A.warn people in airplanes of possible dangers
B.offer some advice on avoiding health problems
C.explain the causes and effects of hypoxia
D.a(chǎn)dvise people not to smoke or drink alcohol
64.According to the passage,what leads to hypoxia?A
A.The brain lacks enough oxygen.
B.The air pressure in a plane is too high.
C.Our body needs less oxygen during takeoff.
D.The bloodstream contains no oxygen molecules.
65.The underlined part"fix the situation"means"D".
A.use more oxygen it needs
B.increase the air pressure
C.reduce the amount of blood
D.bump more blood to the brain
66.Why should passengers not smoke or drink before flying?A
A.They weaken the body's ability to use oxygen.
B.Smoking may pollute the air inside the airplane.
C.Drinking alcohol may raise one's blood pressure.
D.Drinking is forbidden at the airport.
分析 文章講述的是關(guān)于坐飛機(jī)旅行時(shí)會(huì)出現(xiàn)的缺氧癥的原因和造成的后果.
解答 CADA
63:C 推理判斷題,根據(jù)第一段的Experts say people should know about other health problems that can strike when traveling by air可知,文章是向讀者解釋缺氧癥的原因和后果.
64:A 事實(shí)細(xì)節(jié)題,根據(jù)第二段It results from a lack of oxygen to the brain可知,是由于大腦缺氧導(dǎo)致
65:D 推理判斷題,根據(jù)第三段內(nèi)容可知,解決這種情況指的是給大腦提供更多的血液.
66:A 事實(shí)細(xì)節(jié)題,根據(jù)最后一段Experts say that smoking cigarettes and drinking alcoholic liquids also reduce the body's ability to use oxygen可知,
點(diǎn)評 做閱讀時(shí)經(jīng)常犯錯(cuò)的主要原因是,僅憑讀過文章后殘留在腦海中的一絲印象來勾選答案,這樣便很容易掉入出題人故意設(shè)布下的題目陷阱.所謂閱讀理解,對于題目的理解一定要忠實(shí)于原文,因此,每一道題都應(yīng)該與原文作全面的對比與核查,再得出答案.也就是說,閱讀理解的每一道題目,在原文都應(yīng)該有明確的出處,我們把這一出處叫做原文相關(guān)句,(1)排除與原文相關(guān)句主題不一致的選項(xiàng)(2)排除與原文相關(guān)句態(tài)度相反的選項(xiàng) (3)排除用于過于極端或負(fù)面的選項(xiàng)(4)注意結(jié)合文章主旨和主題去排除.