keen as mustard extremely eager or enthusiastic. British informal
☞ In the literal sense of the phrase, keen means 'operating on the senses like a sharp instrument'.
英语词组固定搭配大全包含15956条英汉双解词组，基本涵盖了全部常用英文词组、短语的翻译及用法，是英语学习的有利工具。