A:1∶3
B:3∶1
C:1∶2
D: 2∶1
关于灭菌和消毒的不正确的理解是( )
物质
X
Y
Z
W
反应前质量/g
10
3
90
0
反应后质量/g
3.2
待测
“When____ (meet) bad people, don't be afraid.” Father told me.