A:knew
B:doesn't know
C:will know
D:didn't know
一定质量含杂质的铁(杂质不溶于水,也不参与反应)与100克16% CuSO4溶液恰好完全反应,过滤得到干燥的固体6.8克,则含杂质的铁的质量是( )
— Does Mr. Li know giraffes?
— Yes, .
“天苍苍,野茫茫,风吹草低见牛羊”描写的是 牧区的景观( )