He has accepted the job because he likes challenge, and the chance of dealing with difficult problems ____ to him.

A．appeals

B．interests

C．deserves

D．encourages

在锅炉内部进行检修工作前，须把该炉与蒸汽母管、给水母管、排污母管、疏水总管、加药管等的联通处用（）的堵板隔断，或将该炉与各母管、总管间的严密不漏的阀门关严并上锁，然后挂上警告牌。电动阀门还须将电动机电源切断，并挂上警告牌。

A.石棉

B.金属

C.有尾巴