EachyearintheUnitedStates,manyblackteenagers_______ofschool,eitherbecausetheycannotkeepuportheyhavetoworktosupporttheirfamily.
Wemust______thattheexperimentiscontrolledasrigidlyaspossible.
Theassociationis________toraisingfundstohelptheblind.
Agreatnumberofsmallpowerstations________(setup)intheircounty sinceliberation.
Inordertolivethekindoflifewewantandtobethepersonwewanttobe，wehavetodomorethanjust________withevents．
