空气滤清器的组成及种类？
滤清器主要由壳体和滤芯组成。 滤清器按滤芯取用材料不同分为纸质的、 织物的（麻布、绒布、毛毡） 、陶瓷的、泡沫塑料的、金属的等。其中采用最普遍的是纸质滤清器和金属滤清器。
暂无解析
Theypromised____eachotherwhentheywenttowork.
Theaeroplane____shewastravelingwasdelayedforthreehoursatleast.
Dr.Yangworked______threedaysago.
Passage3
Questions11to15arebasedonthefollowingpassage:
“...WearenotabouttoentertheInformationAgebutinsteadareratherwellintoit.”Presentpredictionsarethatby1990,aboutthirtymillionjobsintheUnitedStates,oraboutthirtypercentofthejobmarket,willbecomputer-related.In1980,onlytwenty-onepercentofallUnitedStateshighschoolsownedoneormorecomputersforstudentuse.(79)Inthefallof1985,anewsurveyrevealedthathalfofUnitedStatessecondaryschoolshavefifteenormorecomputersforstudentuse.Andnoweducationalexperts,administrators,andeventhegeneralpublicaredemandingthatallstudentsbecome“computerliterate(慢点…的).”“Bytheyear2000knowledgeofcomputerswillbenecessaryinovereightypercentofalloccupations.Soonthosepeoplenoteducatedincomputerusewillbecomparedtothosewhoareprintilliteratetoday.”
Whatis“computerliteracy”?Thetermitselfseemstoimplysoonextentof“knowing”aboutcomputers,butknowingwhat.Thecurrentopinionseemstobethatthisshouldincludeageneralknowledgeofwhatcomputersare,plusalittleoftheirhistoryandsomethingofhowtheyoperate.
Therefore,itisvitalthateducatorseverywheretakeacarefullooknotonlyatwhatisbeingdone,butalsoatwhatshouldbedoneinthefieldofcomputereducation.Todaymostadultsarecapableofutilisingamotorvehiclewithouttheslightestknowledgeofhowtheinternal-combustionengineworks.Weeffectivelyusealltypesofelectricalequipmentwithoutbeingabletotelltheirhistoriesortoexplainhowtheywork.(80)Businesspeopleforyearshavemadegooduseoftypewritersandaddingmachines,yetfewhaveeverknownhowtorepairthem.Why,then,attempttoteachcomputersbyteachinghoworwhytheywork?
Rather,wefirstmustconcentrateonteachingtheeffectiveuseofthecomputerasthetoolis.
“Knowinghowtouseacomputeriswhat’sgoingtobeimportant,wedon’ttalkabout‘automobileliteracy.‘Wejustgetinourcarsanddrivethem.”
11.In1990,thenumberofjobshavingnothingtodowithcomputersintheUnitedStateswillbereducedto________.
A)79millionB)30millionC)70millionD)100million(C)
12.Theexpression“Printilliterate”(Para.1,Line16)refersto________.
A)onewhohasneverlearntprintingB)onewhoisnotcomputerliterate
C)onewhohasneverlearnttoreadD)onewhoisnotabletouseatypewriter(C)
13.Thefirstparagraphismainlyabout________.
A)recentpredictionsofcomputer-relatedjobsB)thewideuseofcomputersinschools
C)theurgencyofcomputereducationD)publicinterestincomputers(C)
14.Accordingtotheauthor,theeffectivewaytospreadtheuseofcomputersistoteach____.
A)whatcomputersareB)howtousecomputers
C)wherecomputerscanbeusedD)howcomputerswork(B)
15.WhichofthefollowingstatementsisFALSE?
A)Whattoteachaboutcomputersshouldbereconsidered.
B)Thosewhoarenoteducatedincomputerusewillfinditdifficulttogetajob.
C)HumansocietyhasalreadyenteredtheInformationAge.
D)Thosewhowanttousecomputersshouldknowhowcomputersoperate.
Theday____(在那天我第一次遇见他)wasthefirstofMayontheGreatWall.
