A:π12
B:π6
C:π3
D:5π6
钛是银白色金属,具有硬度大、熔点高、耐腐蚀等许多优良性能,被誉为“未来金属”.由钒钛磁铁矿提取金属钛的主要流程如图所示:
It was much ____ (noise) after he turned on the radio.
有关城乡规划的叙述,正确的是( )