第六部分 完形填空（共四篇）
第二篇
Avalanche and Its Safety
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 incidence n.發(fā)生（率）
terrain n. 地形，地勢 ski v.滑雪
steep adj.險峻的，陡峭的 complexity n. 復(fù)雜性
注釋:
1．a(chǎn)ngle 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)驗法則”。
3．Additionally：是一個副詞，用來引人新的事實或論點(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)生的最大危險之一”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，此處需要一個關(guān)系代詞，代替slope，所以that是最佳選擇。選項A、C、D均不符合語法。
3．B選項A不符合語法，c和D符合語法，但不符合常識：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是最佳答案。
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，所以C是正確答案。
5．C要確定本題答案的一個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，更證實了選risk是正確的。
6．D第6和第7題可以一起考慮。整個句子的意思是：在坡度大的坡上，雪不會大量堆積。
在較為平坦的坡面，雪不會輕易滑動。
7．B(見6)
8．B理解了句子的意思就不難判斷選項：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是最佳選擇，整個句子的意思是：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A、B和D都能和continuous搭配，從全段的內(nèi)容判斷，只有process是最佳選擇，因為該段描寫的是如何防備雪崩，及如何做好安全措施等一系列問題。
12．A選項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，因為不可能完全消除雪崩的隱患。
14．C該句主句使用的是被動語態(tài)，第二個動詞是pay attention t0的被動形式。l選項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8、C、D均不符合句義。
