Merchantandpassengershipsaregenerallyrequiredtohavealifepreserverforeverypersonaboardandinmanycases,acertainpercentageofsmallersizesforchildren.AccordingtoUnitedStatesrequirements,lifepreserversmustdesign,reversiblecapableofbeingquicklyadjustedtofittheuninitiatedindividual,andmustbesodesignedastosupportthewearerinthewaterinanuprightorslightlybackwardposition.
Sufficientbuoyancy(浮力)tosupportthewearershouldberetainedbythelifepreserverafter48hoursinthewater,anditshouldbereliableevenafterlongperiodofstorage.Thusitshouldbemadeofmaterialsresistanttosunlight,gasoline,andoils,anditshouldbenoteasilysetonfire.?Thepositioninwhichthelifepreserverwillsupportapersonwhojumpsorfallsintothewaterismostimportant,asisitstendencytoturnthewearerinthewaterfromaface-downpositiontoanuprightorslightlybackwardposition,withhisfaceclearofthewater,evenwhenthewearerisexhaustedorunconscious.
Themethodofadjustmenttothebodyshouldbesimple,andself-evidenttouninitiatedpersonseveninthedarkundertheconfusedconditions,whichfollowadisaster.Thus,thelifebereversiblethatitisnearlyimpossibletogetitonwrong.Catches,straps,andtiesshouldbekepttoaminimum.Inaddition,thelifepreservermustbeadjustabletothewidevarietyofshapesandsizesofwearers,sincethisgreatlyaffectsthepositionoffloatingandtheself-rightingqualities.Asuitablelifealsobecomfortabletowearatalltimes,inandoutofthewater,notsoheavyastoencouragetotakeitoffonshipboardwhiletheshipisindanger,norsoburdensomethatithindersapersoninthewaterwhiletryingtoswim.
1.Thepassageismainlyabout____.
A)theusesoflifepreservers
B)thedesignoflifepreservers
C)thematerialsforlifepreservers
D)thebuoyancyoflifepreservers
2.Accordingtothepassage,alifebefirstofall____.
A)adjustableB)comfortableC)self-evidentD)self-righting
3.UnitedStatesCoastGuarddoesNOTrequirethelifepreservertobemade____.
A)withasfewstringsaspossible
B)capableofbeingwornonbothsides
C)accordingtoeachwearer'ssize
D)comfortableandlighttowear
4.By“theuninitiatedindividual”(Para.1,Line.4)theauthorreferstotheperson____.
A)whohasnotbeeninstructedhowtousealifepreserver
B)whohasalittleexperienceinusingalifepreserver
C)whousesalifepreserverwithoutpermission
D)whobecomesnervousbeforeadisaster
5.Whatwouldhappenifapersonweresupportedbythelifepreserverinawrongposition?
A)Thewaveswouldmovehimbackwards.
C)Hewouldimmediatelysinktothebottom.
D)Hewouldbeexhaustedorunconscious.
1.B。文章主要讲述了救生衣的设计。间接题型段首主旨题。C项和D项都是对救生衣设计中设计材料的说明。A项为陷阱，指救生衣的用途，尽管开头提到，但范围不着边际。故只有B是正确选项。
2.D。根据文章，救生衣首先会自动扶正。事实细节题。本文第三段主要讨论救生衣落水位置，应设计的能“自动扶正”,或稍向后仰。B项是对材料的描述，范围太窄，而A和C不合题意，因此D是正确答案。
3.C。美国海岸巡逻队不需要救生衣根据穿戴者的尺寸生产。事实细节题。A项和B项都涉及method，其相关部分见最后一段第三句，A，B，D三项都是文章中提及的，C项与本题无关的内容，因此应该选C。
4.A。“theuninitiatedindividual”作者指的是不知道怎么使用救生衣的人。语义指代题。根据文章最后一段第一句，我们可推出“theuninitiatedindividual”就是指的那些不知道怎么使用救生衣的人。故A是正确选项。
5.D。如果一个人没有正确使用救生衣，就会发生什么?细节辨别题。第三段第一句后半句中aface-downposition和本题中的inawrongposition相对应。因此选项D“他可能太累了或者是已经失去知觉”是正确答案。
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