Afternoon tea was introduced in England by Anna, the 7th Duchess of Bedford, in the year 1840, _____ the evening meal was served fashionably late at 8 o’clock, thus _____ a long period of time between lunch and dinner.  

A．in her household… leaving

B．in whose household…leaving

C．in her household…left

D．in whose household…left

无阀滤池过滤水量太大会冲乱滤池中的滤料，降低过滤效果。