单词	empty-set
释义	请查阅词条：empty set
随便看	I feel you i-feel-you I feel your/his, etc. pain if ever there was one if-ever-there-was-one iffy if I may be/make so bold (as to) if-i-may-be-make-so-bold-as-to if it ain't broke, don't fix it if-it-ain-t-broke-don-t-fix-it if it/a thing is worth doing, it's worth doing well importance of diversity importance of diversity importance of education importance of innovation importance of innovation importance of innovation importance of innovation importance of literacy importance of literacy importance of prevention importance of prevention importance of prevention importance of prevention importance of teaching