∵sinα=12,α是锐角,
∴α=30°.
Cambridge ______ a population of about 100,000 people. [ ]
A. have
B. has
C. there is
D. there are
根据现行《火灾自动报警系统设计规范》,火灾自动报警系统的传输线路和50V以下供电的控制线路,应采用电压等级不低于交流()的铜芯导线或铜芯电缆
A.500V
B.380V
C.250V
D.220V