题目

中国古代的四大发明对现代世界的形成曾起重要作用，其中直接推动发现美洲新大陆的是 A.指南针      B.造纸术      C.印刷术       D.火药 答案：A 解析: 略— I heard the phone ringing in the office next door. — You _______ it. They haven’t got a phone yet.A．couldn’t hear B．couldn’t have heard C．didn’t hear D．wouldn’t have heard