离心泵流量调节可通过（）、（）进行。
参考答案：出口阀；旁路或电机变频
_____ the three deaths in the region, one person was also left missing from the April 25 sandstorm.
A．In spite of
B．Apart from
C．Separate from
D．Regardless of
写出下列溶液中溶质的化学式：
稀硫酸______，酒精溶液______，硫酸铜溶液______，澄清的石灰水______，盐酸______，生理盐水中的溶质______．
