indispensable是什麼意思

例句：

She was becoming indispensable to him.

對他來說她正變得不可或缺。

She made herself indispensable to the department.

她成爲這個部門不可缺少的一分子。

Cars have become an indispensable part of our lives.

汽車已成了我們生活中必不可少的一部分。