— The iPhone 4s has been on the market for some time. Have you got one?

— Yes, I________one during my visit to Hong Kong. [    ]

A. have bought       

B. bought

C. had bought       

D. would buy

某技工在铸造钴铬支架时，合金刚熔解就飞溅，可能是

A．合金熔解过度

B．中熔合金的坩埚熔解高熔合金

C．合金中有杂质

D．合金熔解方式不正确

E．高熔合金的坩埚熔解中熔合金