某漂白粉的成分为次氯酸钙和氯化钙(由氯气与石灰乳恰好反应制得)，其溶液中离子浓度大小关系正确的是 [ ]

A．c(Cl^－)>c(Ca^2＋)>c(ClO^－)>c(H^＋)>c(OH^－)

B．c(Cl^－)＝c(Ca^2＋)>c(ClO^－)>c(OH^－)>c(H^＋)

C．c(Cl^－)＋c(OH^－)＋c(ClO^－)＝c(Ca^2＋)＋c(H^＋)

D．c(Ca^2＋)＝2c(Cl^－)＋2c(ClO^－)

— Do you know _________?      —No, I don’t know.

A．where he’s from

B．where is he come

C．where does he come from

D．where comes he from