essential与 necessary的区别

essential与 necessary的区别 crucial与necessary的区别 necessary 与 important的区别. significant与 essential区别 indispensable ,essential ,crucial 三词个的区别是什么? necessary的意思是必须时,能和essential替换吗 needed与necessary有什么区别 be necessary for和 be necessary to的区别 请问essential和important在用法上的区别 should和necessary的区别?以及用法? It's necessary / important / essential that we (should) clea The possession of a passport is essential/necessary for fore