—___________ do you sleep every day? —More than 8 hours.

A．How often

B．How long

C．How much

D．How many

PS凝聚过滤器（F-L03B）的作用是防止（）进入仪表风系统。

A.干燥剂颗粒或灰尘

B.油

C.水

D.油和水