expert/ˈekspɜːt/
adj.（常与at, in连用）内行的At a special swimming pool in Los Angeles, children become expert at holding their breath under water even before they can walk.在洛杉矶的特别游泳池里，孩子甚至在会走路之前就能熟练地在水下屏住呼吸。
Rex soon became an expert at opening the gate.雷克斯很快就成了开门能手。
Kate's an expert in / at / on teaching small children.凯特是个幼儿教育专家。
All the young men are expert drivers.所有这些年轻人都是驾驶能手。