—Mr. Smith, would you please speak a little more ________?—Sorry! I thought you could follow me.
A:quietly
B: slowly
C:quickly
D:politely
动物细胞中的能量转换器是( )
某工厂排出的废水中含有大量的Fe2+、Cu2+和SO42﹣.
Ⅰ某校研究性学习小组设计如图流程以回收铜和硫酸亚铁.请回答: