危险信号灯开关一般装在（）上，这个开关有两个作用，一是（）；二是当开关接通时，开关将（）起来。
参考答案：仪表板；控制电路中的电流；左右两边的转向信号灯并联
Impressive ____, it fades next _____ the story of Armstrong's struggle against disease. [ ]
A. as is the record; by
B. as is the record; on
C. as the record is; for
D. as the record is; to
耐酸砂浆应分层涂抹，每层厚度控制在______。
A．1mm左右
B．3mm左右
C．5mm左右
D．7mm左右
