Someone who is expert at doing something is very skilled at it.
The Japanese are expert at lowering manufacturing costs.
日本人在降低生产成本方面很在行。
If you say that someone has expert hands or an expert eye, you mean that they are very skilful or experienced in using their hands or eyes for a particular purpose.
Harvey cured the pain with his own expert hands.
哈维用他那行家之手消除了病痛。
Expert advice or help is given by someone who has studied a subject thoroughly or who is very skilled at a particular job.
We'll need an expert opinion.
我们需要专家的意见。
experts
An expert is a person who is very skilled at doing something or who knows a lot about a particular subject.
a yoga expert.
一位瑜伽专家。
Health experts warn that the issue is a global problem.
健康专家们警告说这个问题是全球性的。
an expert on trade in that area.
那个地区的贸易专家。