中国航天馆使用的聚氯乙烯膜表面涂有一层二氧化钛（TiO₂）光触媒涂层，具有抗污、吸收紫外光和净化空气的作用．TiO₂中Ti的化合价为（　　）

A．-2

B．+1

C．+2

D．+4

--- Excuse me, can I have a talk with Mr. Miller this afternoon?

---A moment, please. Let me check_______.

A．if Mr. Miller will be free

B．when will Mr. Miller have time

C．if Mr. Miller had a meeting

D．when does Mr. Miller come back