— .
— It's cloudy.
A:How's the weather like today?
B:How's the weather today?
C:What is the weather today?
D:Which is the weather today?
化学方程式2Na2O2+2H2O=4X+O2↑中X的化学式为( )
①中淡黄色的是____
②中含有的血细胞是____和____
③中含有的血细胞是____,其作用主要是运输____.
世界上水量最大、流域面积最广的河流是( )