An avalanche is a sudden and rapid flow of snow, often mixed with air and water, down a mountainside. Avalanches are 1 the biggest dangers in the mountains for both life and property.
All avalanches are caused by an over=burden of material, typically snowpack, that is too massive and unstable for the slope 2 supports it. Determining the critical load, the amount of over-burden which is 3 to cause an avalanche, 4 a complex task involving the evaluation of a number of factors.
Terrain slopes flatter than 25 degrees or steeper than 60 degrees typically have a low 5 of avalanche. Snow does not 6 significantly on steep slopes; also, snow does not 7 easily on fiat slopes. Human-triggered avalanches have the greatest incidence when the snow's angle of rest 1is 8 35 and 45 degrees; the critical angle, the angle at which the human incidence of avalanches is greatest, is 38 degrees. The rule of thumb2 is: A slope that is 9 enough to hold snow but steep enough to ski has the potential to generate an avalanche, regardless of the angle. Additionally3, avalanche risk increases with 10 ; that is, the more a slope is disturbed by skiers, the more likely it is that an avalanche will occur.
Due to the complexity of the subject, winter travelling in the backcountry4 is never 100% safe. Good avalanche safety is a continuous 11 , including route selection and examination to the snowpack, weather 12 , and human factors. Several well-known good habits can also 13 the risk. If local authorities issue avalanche risk reports, they should be considered and all warnings should be paid 14 to. Never follow in the tracks of others without your own
evaluations; snow conditions are almost certain to have changed since they were made. Observe the terrain and note obvious avalanche paths where plants are 15 or damaged. Avoid traveling below others who might trigger an avalanche.
詞匯：
avalanche n.雪崩 trigger v. 引起，激發(fā)
snowpack n. 積雪場(chǎng) incidence n.發(fā)生(率)
terrain n. 地形，地勢(shì) ski v.滑雪
steep adj.險(xiǎn)峻的，陡峭的 complexity n. 復(fù)雜性
注釋:
1.angle of rest：這里指積雪保持靜止的角度。
2.rule of.thumb：指“a broadly accurate principle，based on experience or practice rather that theory”，即“通用法則，經(jīng)驗(yàn)法則”。
3.Additionally：是一個(gè)副詞，用來引人新的事實(shí)或論點(diǎn)，意為“此外”。
4.backcountry：人煙稀少的地區(qū)。
練習(xí):
1. A among B of C to D in
2. A when B that C who D whose
3. A mostly B likely C clearly D surely
4. A are B will be C is D was
5. A weight B form C risk D work
6. A fall B flow C roll D gather
7. A fall B flow C roll D gather
8. A among B between C with D for
9. A thick B thin C flat D rocky
10. A use B time C snow D rain
11. A journey B trip C fact D process
12. A conditions B reports C forecast D event
13. A increase B reduce C improve D remove
14. A price B effort C attention D money
15. A missing B grown C big D fresh
答案與題解：
1.A表達(dá)“雪崩是山上可能發(fā)生的危險(xiǎn)之一”的意思，因此應(yīng)該選擇among(在……之中)。
2.B從該句的語法結(jié)構(gòu)上來看，此處需要一個(gè)關(guān)系代詞，代替slope，所以that是選擇。選項(xiàng)A、C、D均不符合語法。
3.B選項(xiàng)A不符合語法，c和D符合語法，但不符合常識(shí)：過度的雪的積壓可能導(dǎo)致雪崩，
而不是必定導(dǎo)致雪崩。所以，B是答案。
4.C該句的主語是Determining the critical load，從上下文來看應(yīng)該使用一般現(xiàn)在時(shí)，所以C是正確答案。
5.C要確定本題答案的一個(gè)有效的方法是排除法。a.10w weight/form work of avalanche都不合邏輯，只有a low risk of avalanche符合上下文的意思。下面的句子解釋了low risk of avalanche的道理，更證實(shí)了選risk是正確的。
6.D第6和第7題可以一起考慮。整個(gè)句子的意思是：在坡度大的坡上，雪不會(huì)大量堆積。
在較為平坦的坡面，雪不會(huì)輕易滑動(dòng)。
7.B(見6)
8.B理解了句子的意思就不難判斷選項(xiàng)：雪在靜止?fàn)顟B(tài)下，角度在35_45度之間，最可能發(fā)生人為觸發(fā)的雪崩。between：在……之間。
9.C這個(gè)句子說明的是什么樣的山坡最易發(fā)生雪崩，即，A slope that is flat enough to hold snow but steep enough to ski。flat在此做“平坦”解，與后面的steep形成反義。
10.A句中的that is表明，后半部分是對(duì)前半部分的進(jìn)一步說明。所以，這里的選擇要根據(jù)下文的意思判斷。use是選擇，整個(gè)句子的意思是：山坡被滑雪者使用的越多，雪崩就越可能發(fā)生。 、
11.D盡管選項(xiàng)A、B和D都能和continuous搭配，從全段的內(nèi)容判斷，只有process是選擇，因?yàn)樵摱蚊鑼懙氖侨绾畏纻溲┍溃叭绾巫龊冒踩胧┑纫幌盗袉栴}。
12.A選項(xiàng)A、B、c都可以與weather搭配，但是根據(jù)上下文，只有A最為符合文章的內(nèi)容。
13.B選項(xiàng)A不符合句子的意思;c不能和risk搭配;D也不符合句子的意思，因?yàn)椴豢赡芡耆┍赖碾[患。
14.C該句主句使用的是被動(dòng)語態(tài)，第二個(gè)動(dòng)詞是pay attention t0的被動(dòng)形式。l選項(xiàng)A、B、D均不符合句子的意思。
15.A該句是作者給出的一系列忠告之一，即，認(rèn)真觀察地形，注意明顯的雪崩路徑：沒有植物或植物被毀壞的地方。選項(xiàng)8、C、D均不符合句義。
Taking a Nap During the Day
Medical experts say most Americans do not get 1 sleep. They say more Americans need to rest for a short period in the middle of the day. They are advising people to sleep lightly before 2 with other activities.
One study earlier this year found that persons who sleep for a few minutes during the day were less 3 to die of disease. The study followed more than 2,300 Greek adults 4 about six years. Adult who rested for half an hour 5 three times a week had a 37 percent lower risk of dying from heart disease than those who did not nap.
Study organizers said the strongest evidence was in working men. They said naps might improve 6 by mitigating tension caused by work.
Some European and Latin American businesses have supported the 7 of napping for many years. They urge people to 8 work, go home and have a nap before returning. In the United States, some companies let workers rest briefly in their offices. They believe this reduces in their offices. They believe this reduces 9 and accidents, and 10 increases the amount of work a person can do.
Sleep experts say it is likely that people make more mistakes at work than at other times1. They say people should not carry out important duties when they feel 11 . And they say the best thing to do is to take a nap. About twenty minutes of rest is 12 you need. Experts say this provides extra energy and can increase your effectiveness 13 the end of the day. But experts warn that a nap 14 last no more than twenty to thirty minutes. A longer nap will put the body into deep sleep2 and waking up3 will be 15
詞匯:
Nap n. 打盹 mitigate v.減價(jià)
urge v.催促，勸告
注釋:
1.people make more mistakes at work than at other times：人們?cè)诠ぷ?時(shí)間)中出錯(cuò)的概率比其它的時(shí)間要多。本句中的at work可以理解為during their work time。
2.put…into deep sleep：使……進(jìn)人深睡狀態(tài)
3.waking up：從上下文判斷，waking up是“自己醒過來”的意思，不是“喚醒”。
練習(xí):
1. A sweet B sound C bad D enough
2. A checking B sharing C continuing D meeting
3. A lovely B likely C fondly D finely
4. A for B at C in D with
5. A at least B at most C at last D at first
6. A ability B health C thinking D life
7. A experiment B reform C idea D way
8. A repeat B improve C change D leave
9. A work B mistakes C energy D time
10. A never B seldom C too D also
11. A ready B good C sleepy D awake
12. A all B few C any D nothing
13. A unless B while C until D during
14. A would B may C might D should
15. A helpful B difficult C easy D happy
答案與題解:
1.D本段第二句說“more Americans need to rest for a short period in the middle of the day”。引導(dǎo)我們選擇(not)enough。因?yàn)樗卟粔�，才要中午“打個(gè)盹”。選項(xiàng)A：文不對(duì)題。選項(xiàng)B：bad(sleep)與上下文不符，因?yàn)橥ㄆ恼聸]有提到過，中午打盹的原因是晚上沒有睡好。選項(xiàng)C：明顯不合乎邏輯�！坝捎跊]有睡不好(即：晚上睡好了)，白天還要補(bǔ)睡一會(huì)兒”，于理說不通。所以，惟一合理的選擇是enough。 ’
2.C空格2所在句子的意思是：醫(yī)學(xué)專家建議人們?cè)谶M(jìn)行其它活動(dòng)之前，小睡一會(huì)。四個(gè)選項(xiàng)中，只有continuing(選項(xiàng)C)最接近上述的理解。
3.B空格3所在的句子說的是“心臟病致死”的問題，lovely，fondly和finely分別表達(dá)“可愛”、“喜歡”和“美好”的意思，明顯不對(duì)。less likely是“可能性較低一些”的意思，選擇likely符合上下文的意思。本段最后一句說，成年人白天打盹半小時(shí)，一周三次，其心臟病致死的概率比不打盹的人要低37%。這更證實(shí)了選likely是正確的。
4.A本句的意思是，調(diào)查進(jìn)行了六年。about six years之前要用表達(dá)一段時(shí)間的介詞for。介詞at和with明顯與about six years不搭配，而選項(xiàng)in(about six years)表達(dá)的是未來的時(shí)間，如：He will come to Beijing in one day or tw0.(他一、兩天之內(nèi)會(huì)到北京。)
5.A at first和at last明顯與本句的意思不符。若選at most(最多)，本句的意思成了“成年人白天打盹半小時(shí)，一周不得超過三次，其心臟病致死的概率比不打盹的人要低37%”，意思有點(diǎn)令人費(fèi)解。改說成，“一周至少三次”才說得通。所以at least是答案。
6.B通篇文章在闡述白天打盹有益于健康，選項(xiàng)B是答案。
7.C空格7所在的句子的意思是：多年來，歐洲和拉丁美洲的一些公司支持白天打盹的 ? (空格中填哪一個(gè)詞?)。很明顯，空格中填入experiment(試驗(yàn))或reform(改革)則離題太遠(yuǎn)，而way(方式)肯定沒有idea(想法)好。C是答案。
8.D從上下文判斷，空格8的詞應(yīng)該與“中止(work)”有關(guān)。四個(gè)選項(xiàng)中，只有l(wèi)eave合乎這一條件。而其它三個(gè)選項(xiàng)repeat(重復(fù))、improve(改進(jìn))和change(改變)與后半句的go home and have a nap搭不上。
9.B前面一句說，美國有些公司讓職員在辦公室打個(gè)盹，這樣可以減少些事故等。填人空格9的詞應(yīng)該與accidents(事故)一樣，是一個(gè)負(fù)面意思的詞。mistakes(選項(xiàng)B)符合這個(gè)條件，是答案。reduce work/energy time都不合理。
