"adept in handicrafts"
"an adept juggler"
"an expert job"
"a good mechanic"
"a practiced marksman"
"a proficient engineer"
"a lesser-known but no less skillful composer"
"the effect was achieved by skillful retouching"
"technical terminology"
"a technical report"
"technical language"
He is expert at/in painting.
他的专长是画画。
He is an expert on/at/in lung diseases.
他是肺部疾病方面的专家。