单选题 They are sure they have all the facts they need to ______ the existence of a black hole.
【正确答案】 C
【答案解析】verify意为“证实”。obtain意为“获得,得到”。maintain意为“保留,维持,维修”。display,意为“展览,展示,显示”。句意:他们确信拥有全部事实证实黑洞的存在;