Mustard 是“芥末”, 这个短语是什么意思呢？请看对话：

    A: John has asked me to help him find a job. But isn’t he working for a trading firm now?

    B: I’ve heard that his boss fired him because he couldn’t cut the mustard.

    Note: The idiom means to “succeed, come up to expectations.” Some say this is another form of the idiom “pass muster,” but that seems unlikely. Why cutting mustard was chosen as an example of high quality is unclear. Some explanation alludes to the literal difficulty of cutting mustard in its various forms. For example, mustard seed is hard to cut with a knife on account of its being small and shiny. Others link mustard to something that adds flavor and zest.