例句：
He considers himself an expert on the subject.
他认为自己是这门学科的专家。
He earned a reputation as an expert on tax law.
他赢得了税法专家的美名。
We employ an expert to advise on new technology.
我们聘用了一位专家担任新技术顾问。
I don't profess to be an expert in this subject.
我不敢自诩为这方面的专家。
Harvey cured the pain with his own expert hands.
哈维用他那行家之手治愈了那病痛。