Collecting stamps ______ my father’s favorite hobby and reading novels ______ my mother’s favorite pastime.

A．are; is

B．is; are

C．is; is

D．are; are

网式过滤器是由一层或两层（）网作为过滤材料，包在金属或塑料骨架上而成。

A、铜丝

B、铁丝

C、钢丝

D、塑料