药物混合的均匀性与下列哪些选项无关
A.药物粉末的分散度B.药物粉末的体积与辅料体积之比C.药物粉末的密度与辅料密度之比D.药物粉末的形态E.以上答案都不对
参考答案:B
一个梯形花台,上底长12米,下底长18米,高10米.这个花台的占地面积是多少平方米?
When my father got home, I ______ a letter to my friend. [ ]
A. write
B. am writing
C. wrote
D. was writing