下列化学方程式书写正确的是（   ）

A．S + 2OSO₂　

B．KClO₃="=KCl" + O₂↑

C．2H₂ + O₂2H₂O　

D．Mg + O₂MgO₂

Man: I have to phone my secretary before we leave.
Woman: There is not much time. Maybe you’d better get Tom to phone for you.
Question: What does the woman mean().

A. He should ask Tom to call the secretary.

B. He can’t use the secretary’s phone.

C. There’s not enough time to phone Tom.

D. The secretary will leave before he does.