于123℃左右，液体培养基需要灭菌（）。
参考答案：20min
A good friend of mine from _________- I was born showed up at my home right before I left for Beijing.
A．how
B．whom
C．when
D．which
涡街流量计属于（）式流量计。
A.质量
B.差压
C.速度
D.容积
