—I have      notebook and two pens in my bag.      notebook is for you.

—Thank you.

A．a; A

B．the; The

C．the; A

D．a; The

用双硫腙比色法测定铅时，为了消除其他金属离子的干扰，应采取的措施是（）。

A、控制pH=8.5～9.0

B、加氰化钾

C、加柠檬酸铵

D、加盐酸羟胺