你这句话是疑问句,你想想看陈述句怎么说?
就是The cup is made of pure gold.那么问的时候就应该把is给放到句首
道理很简单,就好像我可以说It is a cup但是不能说It does a cup一样.那么问的时候就应当是Is it a cup?而不是Does it a cup,反之亦然
再说了,如果你问Does the cup made of pure gold?那别人怎么回答?难道是Yes,it does a cup或者Yes,it makes a cup吗?不行吧?