英文学术论文科技论文应注意常用的动词时态

,,。“”,,,。,。,,、、、,。“,”,“”。,,,,,。,。19962000,。,2000199694%。,,。、、“”,,,。、,,,,,,,,,……,。,,,。,。□哈尔滨理工大学《电机与控制学报》编辑部　王长风编辑英文科技论文应注意常用的动词时态　　WTO,。,。,,,,。,21。,,,4,,。1　,,[1],。,。,,,,[2]:Thispieceofmetalexpandedwhenitwasheat-ed.Itwillcontractwhencooled.,,,。,,:Metalsexpandwhenheatedandcontractwhencooled.,,,:Thechickembryosarechoppedupandareputintoajar.,:Newtonfoundthatallmassesattracteachother.WillmendiscoverthatthereislifeonMars?,、,36　　　　　　　　　　　　　　　2002　　2　　　　　　　　　　　业务交流　WORKINGDISCUSSION,。,:(1):Thecrudeoilthenpassesdownthepipeline.(2):Waterfreezesat0℃.(3):Thistypeofvinegarcontainsabout3%acid.(4):Actionandreactionareequalandopposite.(5)::f=ma:Forceappliedequalsmasstimesaccelerationproduced.:X∝1/y:Xvariesinverselyasy.(6):Adiodevalvecontainstwoelectrodes.(7):Thetemperaturerisesuntilitreaches100℃,butafterthatitremainconstant.2　,,?[3]:,,,。:Torricelli:First,alongglasstubeistaken.Thetubeisclosedatthetopandisthencompletelyfilledwithwater....。Torricelli。:Theweightofairaboveourheadswasfirstmea-suredbytheItalianscientistTorricelliin1643.Hetookalongglasstube.Heclosedthetubeatthetopandthencompletelyfilledthetubewithwater....,。,,。,()。,。:···()3　,、,、,。:Wearenowlookingatanotherprocess.Theheatedplasticmaterialisbeingextrudedthroughadie,intheformofthreads.Thethreadsarenowbeingdrawnthroughabath,tocoolthem.Nowtheyarebeingchoppedintogranules.:Wearenowlookingatanotherprocess.Theheatedplasticsmaterialisbeingextrudedthroughadie,intheformofthreads.Thethreadsarenowdrawnthroughabath,tocoolthem.Thentheyarechoppedintogranules.,。:isextruded,aredrawn,arechopped。,(“now”,,“then”)。,,:(1):Whiletheliquidsarereacting,heatisevolved.(2)、:Thisyearwearetestinganewcontrolsystem.(3):Itisnowbecomingclearthatthismethodwillnotwork.4　,,37　　　　　　　　　2002　　2　　　　　　　　　　　　　　　　　业务交流　WORKINGDISCUSSION,,。:(1),:Workhasbeenstarted.Theyhavestartedwork[4].(2)“”,,。[3]:a):Anetworkofcommunicationsatelliteshasbeenes-tablished.b):Varioustypesofreactorhavebeendesignedfordifferentpurposes.c),,:Medicinehasmadegreatprogressinthelasttwentyyears.d)already,notyet,for,since,just,recently,lately:Theresearchteamhasjustpublishedadescriptionofthenewalloy.e)“It++that”:,,(,:Itwillbeobservedthatsomeofthechalkhasnotdissolved.):IthasthereforebeenshownthatanglesABCandDEFareequal.f),,when,that,inwhich,:Whensufficientliquidhascollectedinthebeakeritshouldberemoved.,。。(a)0℃※100℃　Heatthewateruntilitboils.。(a′)0℃※100℃※100℃　Heatthewateruntilithasboiledaway.。(b)Turnofftheburnerwhenthesubstancecatchesalight.。(b′)Turnofftheburnerwhenthesubstancehasbeenreducedtoash.。(a)(b),,。(a′)(b′),,。(b′)Turnofftheburnerwhenthesubstanceisreducedtoash,,。:(1),:Turnofftheburnerwhenthesubstancehasbeenleftintheflameforthreeminutes.(,。)(2),:Ironexpendswhenitisheated.5　、,。,,。,[5]。、3,。,。1　.111[M].:,19992　BBCEnglishbyRadioandTelevision.Scientificallyspeaking[M].London:BBC,19713　·.[M]..:,19804　AJ.[M].,.:,19805　.[M].:,1992□38　　　　　　　　　　　　　　　2002　　2　　　　　　　　　　　业务交流　WORKINGDISCUSSION