对中子射线的屏蔽可选用：（）
A、低原子序数的材料（铝、塑料或有机玻璃等）C
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Directions:
Inthissection,thereare10incompletesentences.Youarerequiredtocompleteeachonebydecidingonthemostappropriatewordorwordsfromthe4choicesmarkedA,B,CandD.ThenyoushouldmarkthecorrespondingletterontheAnswerSheetwithasinglelinethroughthecenter.
21、62%ofthepeoplesurveyedsaidtheyalwaysavoided______theirsmartphonesduringmeals.
A.useB.usingC.touseD.used
22、TheHRdepartmentisacriticalpartofemployeewell-beinginanybusiness,nomatter______smallitis.
A.howB.whatC.whereD.which
23、Accordingtotheregulation,inspections______toensurethatthesystemsareingoodcondition.
A.demandedB.havedemandedC.bedemandedD.aredemanded
24、Beforeyouthinkaboutaskingforapromotion,makesurethateitherapositionopeningexists______anewpositionisneededtobecreated.
A.andB.norC.orD.but
25、ThetrafficwasmakingsomuchnoisethatIcouldn'thearwhathe______.
A.issayingB.wassayingC.hassaidD.willsay
26、Ourcompanycultureis______makesussuccessfulincreatingafriendlyandexcitingenvironment.
A.whereB.howC.whatD.why
27、Mostpeopleweregreatlyshockedbythenews______theITcompanyhadgonebankrupt.
A.whatB.howC.whyD.that
28、IwouldprobablytrytofindabetterjobifI______inyourposition.
A.amB.wereC.havebeenD.be
29、Ifyouare______busytoattendthemeeting,youcansendyourassistanttotakeyourplace.
A.veryB.soC.tooD.more
30、Ihadtowaitforanothertwomonthstobeabletohavethecar______.
A.fixingB.fixC.tofixD.fixed
在制作图象映射时，可以
特种设备生产单位()生产许可证的，责令停止生产，处五万元以上五十万元以下罚款;情节严重的，吊销生产许可证。
失事后将造成下游灾害严重影响工程效益的建筑物称为（）。
帷幕灌浆，表层孔段的灌浆压力不宜小于（）倍帷幕的工作水头。
