题型:名词解释 People _______the southwest of China were in great need of water a couple of months ago.A.inB.atC.toD.on 查看答案
题型:名词解释 ()的阀门在开度小时,流量相对变化值大,灵敏度高,不易控制,甚至发生振荡,而在大开度时,流量相对变化值小,调节缓慢,不够及时。A.快开特性B.等百分比特性C.直线特性D.抛物线特性 查看答案