【Myneighourmustmakemoney_______thoughheisover70yearsold.---Why?Theold_______lookedafterwellbythegovernmentinChinanow.A.byhimself;isB.byherself;areC.byhimself;areD.byherself答案上选着B,为什么是第二个选项】

　　Myneighourmustmakemoney_______thoughheisover70yearsold.---Why?Theold_______lookedafterwellbythegovernmentinChinanow.A.byhimself;isB.byherself;areC.byhimself;areD.byherself答案上选着B,为什么是第二个选项为什么是are,不是单数吗?