二氧化硫转化用的钒催化剂为多相催化剂。
参考答案：对
There are books on the shelf. And them is about three hundred.
A．a number of; a number of
B．the number of; the number of
C．a number of; the number of
D．the number of; a number of
培养白喉棒状杆菌应选择哪种培养基
A．SS培养基
B．Loeffler血清斜面培养基
C．沙氏培养基
D．麦康凯培养基
E．中国蓝培养基
