It is essential that human____ ways and means to protect the environment.

题目

It is essential that human____ ways and means to protect the environment.
A.adopt B.have adopted C.will adopt D.will have adopted

答案

选A.
It is +essential等形容词后,that主语从句中用虚拟形式should do sth(should可以省略),这类形容词包括necessary,important,essential,imperative,urgent,preferable,vital,advisable等,例如It is necessary that you listen to the teacher carefully.或者It is essential that you be able to pronounce every single word correctly.