He has nothing to do today, _____?

[      ]

A. doesn't he

B. do he

C. does he

D. isn't he

下列关于石灰石/石灰法脱硫的判断错误的是( )。

A．属于湿法脱硫
B．属于抛弃式脱硫
C．主要活性组分为CaO
D．主要产物是CaSO₄和CaSO₃