题目

The policeman told me that I had passed the driving test and never in my life _______ so happy and excited. A. I felt            B. did I feel           C. I had felt                  D. had I felt 答案：D噪声会影响人们的工作和生活，因此控制噪声十分重要，公路两旁的隔音墙是在________（选填“声源处”、“传播途中”或“人耳处”）减弱噪声．在无锡城区步行街上安装了如右图所示的噪声监测装置，该装置显示了噪声的________（选填：“音调”、“响度”、“音色”）．35后面的单位是________.