一、选择题1．IthinkthecoffeebeansarefromBrazil,________I’mnotcompletelysure.A．becauseB．sinceC．thoughD．whether2．Don'tbeafraidofaskingforhelp________itisneeded.A．unlessB．untilC．althoughD．when3．You’ll________thewar________youwatchthefilm.A．feelsadabout;unlessB．feelsadabout;ifC．feelsadwith;unlessD．feelsadwith;if4．—Whenwilltherailwaythatconnectsthetwocitiesopen?—nextyear.Onlytwothirdsbeenbuilt.A．Until;hasB．Until;haveC．Notuntil;hasD．Notuntil;have5．Smilingisthebestpolicy.Peoplewillsmileback________yousmileatthem.A．unlessB．althoughC．untilD．when6．Manypeopledonotrealizetheimportanceofhealth_________theyhavefallenill.A．untilB．whileC．whenD．after7．___________IhearKennyG'srecordingGoingHome,Ialwaysthinkofmyhometown.A．WhileB．SinceC．UntilD．Whenever8．Inancienttimes,peopleseldomtravelledlongdistancesandmostfarmersonlytravelled________thelocalmarket.A．longerthanB．morethanC．asmuchasD．asfaras9．Theoldcoupleinsistonlivinginasmallvillageamongthemountains__________theycangetclosertonature.A．untilB．unlessC．eventhoughD．sothat10．—Doyouoftentakeexerciseinthemorningeveryday?—Yes.Igojoggingeverymorning_______thereisheavyairpollution.A．untilB．unlessC．ifD．as11．Millie’sresearchpaperisn’tuptostandard_________shehasworkedatitfortwoweeks.A．sinceB．unlessC．ifD．although12．—Itisapitythatthediseaseisstillterribleatpresent.—Yes.Itwillbeworse________wetakefurtheractiontodosomethingforit.A．unlessB．sinceC．ifD．when13．We’renotveryclosefriends________we’veknowneachotherforalongtime.A．untilB．althoughC．asD．if14．Samthoughthisrobotbroken________Jimpointedoutthathe’dforgottentoturnitoff.A．untilB．unlessC．afterD．assoonas15．—DidyouwatchtheNewsNetworkShowyesterday?—Yes,ofcourse.Inevermissit________Ihavetoomuchhomework.A．unlessB．untilC．ifD．since16．—_______Dr.ZhongNanshanknewthatCOVID-19wasadeadlynewvirus,hestillwenttoWuhaninCentralChinatohelpthelocalpeople.—Heisreallyabraveandkinddoctor.A．IfB．AssoonasC．BecauseD．Although17．_______Chinahascontro