expert in
Mary es experta en poner cara de póker.
Mary is an expert at keeping a poker face.
Ella es experta en matemáticas.
She is an expert in mathematics.
Mi mujer era experta en artes marciales, y Bi Yen Ju Li la mató.
My wife was an expert in martial arts, and Bi Yen Ju Li killed her.
— Tigre y dragón (2000)