古蔡法中试剂的作用
醋酸铅棉花
A．还原五价砷为三价砷B．检验AsH3C．消除H2S干扰D．使生成AsH3并逸出E．还原催化加速
参考答案：C
This boy is my new friend. _____ hair is red and straight. [ ]
A. Her
B. He
C. His
