To be competent in his field, he must develop a working knowledge of this aspect.

　　為了使自己能勝任所從事工作，必須加深這方面知識。

　　Most adults do not feel competent to deal with a medical emergency involving a child.

　　大部分成年人不懂得如何對兒童實施急救。

　　He was a loyal, distinguished and very competent civil servant.

　　他是一位敬業(yè)、優(yōu)秀而且非常稱職的公務員。