—He was early drowned in a pool.—Oh, when was ______ exactly?

— It was in 1983 _______ he was swimming with his friends.

A．this; that

B．that; when

C．that; that

D．what; when

下列说法正确的是 [ ]

A. 可用铁质容器来配制和盛装波尔多液（波尔多液是熟石灰和硫酸铜配制的农药）

B. 钢铁制品表面一旦生成了红棕色的铁锈，可阻止铁进一步氧化

C. 清洁铝制品时，宜用砂纸打磨其表面，使其恢复金属光泽. 光洁如初

D. 白铁皮（镀锌铁）比铁皮耐腐蚀