调制解调器是同时具有调制和（）两种功能的设备。它是一种信号（）设备。
参考答案：解调、变换
After several sleepless nights, Mr Johnson ________ a perfect solution to the financial problems of his
company. [ ]
A. came up with
B. put up with
C. kept up with
D. ended up with
施工企业在确定建设工程职业健康安全与环境管理目标时，一般事项频率控制目标通常在（）以内。
A.6‰
B.8‰
C.10‰
D.12‰
