it is crucial that those new plants be environmentally sound.主句中为什么动词用了原形?
问题描述：
it is crucial that those new plants be environmentally sound.主句中为什么动词用了原形?
If we are ever going to protect the atmosphere, it is crucial that those new plants be environmentally sound.
答
这是一个典型的虚拟语气.当句子中有crucial,important,necessary等形容词做表语时,后面that引导的主语从句要用虚拟语气,形式是（should）+动词原型,should可以省略掉.