David is             animal fur, so he won^’t visit anyone who has cats or dogs in the house.

A．curious about

B．allergic to

C．satisfied with

D．food of

电气保护管中，常用作保护管的有（）。

A．铝合金电线管

B．镀锌水煤气管

C．金属软管

D．紫铜管