[单选]   二、完型填空：阅读下面的短文，根据文章内容从A、B、C三个选项中选出一个最佳选项将其补充完整。  Filingmeanskeepingdocumentsina    placeandbeingabletofindthemeasilyandquickly.Documentsthatare    willnoteasilytear,getlostordirty.   Afilingsystemisthecentralrecord-keepingsystemforanorganization.Ithelpsallpeoplewhoshouldbeabletoaccessinformationtodosoeasily. Itisalways    whensomeonelooksforsomethingandisabletofinditwithoutdifficulties.Inourorganizationsweworkingroups.Wereceiveandsendoutdocumentsondifferentsubjects.Weneedtokeepthesedocumentsfor    reference.Ifthesedocumentsarenotcaredfor,wecannotaccountforallourorganizationalactivities.Everyonewhoneedstousedocumentsshouldknow    togetthem.A.clean                         B.secret               C.safe2.A.caredfor          B.caringfor            C.carefor3.A.aluck                        B.apleasure                     C.afun4.A.future                        B.past                C.historic5.A.when                         B.why                C.where