如图所示为盒装纯牛奶,它的密度ρ牛奶=1.02g/cm3,则盒内牛奶的质量是 g.
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安全触点的动作应由断路装置使其强制地机械断开,甚至两触点熔接在一起也应强制地机械断开。()
I saw Mr Li into the school library just now.
A.went
B.goes
C.going
D.go