阅读理解

Outdoor Survival Provides Adventure Worldwide

　　Although there are no state controlled survival courses in Britain or the United States,there are various independent organizations offering similar activities．

　　Students can take part in outdoor training courses through university clubs and societies．Anyone can register with such groups,which then organize courses,training and trips for all members．

　　One of the most popular outdoor training programmes in both the US and Britain,is Outward Bound(户外训练)．It was founded in 1941 in Wales and attracts hundreds of thousands of adventurous types every year．

　　The courses are intended to broaden minds through experiences that build confidence,self-esteem(自尊)and character．As well as specialist courses such as canoeing, leadership skills and sailing,participants can take part in week long adventure training camps which include a host of sports and survival training education skills．

　　Michael Williams,an American student,took part in an Outward Bound course last year．He said：“We learned lots of first aid skills,lots of natural history,lots of environmental facts,and took part in a wildlife preservation programme．Beyond that,my favourite skills learned were sailing and rock climbing．”

　　Courses can last up to 40 days and are open to anyone over the age of 14．Students must be in general good health,but do not need to be experienced in outdoor-sports．There is no selection process;everyone is welcome,although new participants are advised to pick a course matching their physical capacity．

　　Most of the British courses take place in the Brecon Beacons in Wales．Another similar organization is the UK Survival School,which includes courses on learning to live with the environment,sailing and winter survival．On a basic survival weekend students will learn how to get water and food,how to make fire and cook with it,to find and build a shelter,control survival life support,how to cross rivers,send off a distress signal,and to use compasses by day and night．

　　According to the leaders,such adventures are “an awakening,an exploration into the unknown”．Outward Bound believes that participants will “use mind and body traveling some of the Earth’s roughest wilderness areas”．

阅读理解

　　What will man be like in the future－in 5000 or even 50 000 years from now? We can only make a guess, of course, but we can be sure that he will be different from what he is today．For man is slowly changing all the time．

　　Let us take an obvious example．Man, even five hundred years ago, was shorter than he is today．Now, on the average, men are about three inches taller．Five hundred years is a relatively short period of time, so we may suppose that man will continue to grow taller．

　　Again, in the modern world we use our brains a great deal．Even so, we still make use of only about 20％ of the brain’s capacity．As time goes on, however, we shall have to use our brains more and more and eventually we shall need larger ones!This is likely to bring about a physical change too：the head, in particular the forehead, will grow larger．

　　Nowadays our eyes are in constant use．In fact, we use them so much that very often they become weaker and we have to wear glasses．But over a very long period of time it is likely that man’s eyes will grow stronger．

　　On the other hand, we tend to make less use of our arms and legs．These, as a result, are likely to grow weaker．At the same time, however, our fingers will grow more sensitive because they are used a great deal in modern life．

　　But what about hair? This will probably disappear from the body altogether in course of time because it does not serve a useful purpose any longer．In the future, then, both sexes are likely to be bald!

　　Perhaps all this gives the impression that future man will not be a very attractive creature to look at! This may well be true．All the same, in spite of all these changes, future man will still have a lot in common with us．He will still be a human being, with thoughts and emotions similar to our own．

Reading Comprehension

　　Imagine being on a treadmill(跑步机), wearing a face mask connected to oxygen-measuring equipment．You are walking at a leisurely pace, at the slowest setting, so your oxygen consumption is fairly low．As the speed of the treadmill increases, your metabolism(新陈代谢)increases, and as a result, your oxygen consumption goes up as well．Your muscle cells are using the extra oxygen to break down carbohydrates, which they use for fuel, and turn them into energy, so their metabolism is said to be aerobic(with air)．You are now jogging along at a comfortable speed, still supplying sufficient oxygen to your muscle cells, so your exercise is still aerobic．As you increase your speed, your oxygen consumption will continue to rise, but at some point, it will stop rising．That is because your heart and lungs have reached their maximum capacity for supplying oxygen to the muscles via the bloodstream．But you can still run a lot faster．Your speed keeps increasing and eventually you are running as fast as you can, but your oxygen consumption has not changed．Your muscle cells can keep on firing without getting the extra oxygen they need because they are able to break down carbohydrates without using oxygen．This is called anaerobic(without air)metabolism．Sprinters(短跑运动员), who run at top speed, perform most of their hundred-meter race anaerobically; in contrast, long-distance runners, who have time to vary their speed, perform most of their event aerobically．

　　Anaerobic metabolism is far less efficient than aerobic metabolism but is capable of generating very high quantities of energy for short periods of time．It also generates lactic acid(乳酸)as a by-product．This is stored in the muscles and associated with muscle fatigue and general exhaustion．That is why sprinting cannot be kept up for very long．After sprinting, the lactic acid that has been stored in the muscles has to be broken down, and this requires oxygen, which explains why we breathe quickly after a hard run．