.Water and air are _______ to human being

未知题型

.Water and air are _______ to human beings. We can not live without them.

A.harbour B.function C.definite D.essential

A.:none;
B.Water and air are _______ to human beings. We can not live without them.C.:none;
D.harbour B.function C.definite D.essential

【参考答案】

选择D，意思是水和空气对人类来说都是必不可少的，我们离开他们无法生存。
essential就是必不可少的意思

知识问答考试试题及答案解析