Astronaut as he was, he didn’t know _______ he had to _______ in outer space.

A．how; deal with

B．what; deal with

C．how; do with

D．what; be done with

铜在体内的主要生理作用包括（）

A、不参与铁代谢

B、不与蛋白交联

C、超氧化物转化

D、构成骨骼和牙齿