绝对需要的，不可缺少的，极重要的...

of the essence的音标：of the essence的英式发音音标为：[ɔv ðə 'esns]of the essence的美式发音音标为：[ʌv ði 'ɛsəns]...

Speed was of the essence in a project of this type.对于这种项目来说，速度至关重要。Speed is of the essence in successfully containing a biological warfare attack.要想成功地扼制生物战袭击,速度十分重要.For many applications, speed is of the essence.对于许多应用软...