下列离子方程式正确的是

A．氢氧化钡溶液中滴加稀硫酸：Ba^2＋＋OH^－＋ H^＋＋SO₄^2- ==BaSO₄↓＋H₂O

B．饱和碳酸钠溶液通入足量二氧化碳后溶液浑浊：2Na^＋＋CO₃^2－＋CO₂＋H₂O ="=2" NaHCO₃↓

C．少量SO₂用氨水吸收：2NH₃·H₂O + SO₂==2NH₄⁺ + SO₃^2－ +H₂O

D．往明矾溶液中加入氢氧化钡溶液至Al³⁺完全沉淀：Al³⁺ + 2 SO₄^2— + 2 Ba²⁺ + 3OH ^— ="=" Al(OH)₃↓+ 2BaSO₄↓

—Do you still remember__________he was taken to the hospital?

—Yes，he was sent to the hospital in Mr Smith’s car.

A．why

B．how

C．when

D．that