The courses were taught by very skilful and talented teachers.

skilful 是形容词，由名词 skill（技能）加上后缀 -ful（表示"充满...的"）构成，意思是"技艺高超的、熟练的"。 在美式英语中通常拼写为 skillful，英式英语则常用 skilful 这种拼写方式。