a quick study
US someone who is able to learn new things quickly:
He lacked foreign policy experience but was a quick study.
Netrebko, who is a very quick study when it comes to languages, speaks English with no noticeable Russian accent.
英语词典包含110679条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。