“But the man, who was called Adam, was all alone and lonely. God said ‘It’s not good for man to be alone. I will make a good companion for him.’” What does the underlined word mean?

A．on one’s own

B．happy

C．unhappy

D．evil

锰铁按碳含量的不同，分为（）三类。

A、普碳类

B、低碳类

C、中碳类

D、高碳类