dispensable /dɪˈspensəbl/

adj.

[not usually before noun] 不必要；可有可无；不重要

not necessary; that can be got rid of

They looked on music and art lessons as dispensable.

他们认为音乐课和美术课是可有可无的。

All those people in the middle are dispensable.

所有那些立场骑墙的人都可要可不要。

indispensable /ˌɪndɪˈspensəbl/

adj.

~ (to sb/sth) | ~ (for sth/for doing sth)

不可或缺的；必不可少的

too important to be without

同义词： essential

Cars have become an indispensable part of our lives.

汽车已成了我们生活中必不可少的一部分。

She made herself indispensable to the department.

她成为这个部门不可缺少的一分子。

A good dictionary is indispensable for learning a foreign language.

一本好词典是学习外语必备的。

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