A:(60+4 2 )π
B:(60+8 2 )π
C:(56+8 2 )π
D:(56+4 2 )π
计算:(3.9×5.5×6.3×3.6)÷(1×3×5×7×0.9×1.1×1.3)=____ .
仙人掌生活在缺水的沙漠中,在仙人掌细胞中含量最多的化合物是( )
I think July is ____ (hot) than any other month in our country. It's ____ (hot) month of the year.
生活离不开化学,下列认识错误的是( )