What he believed still seems to me to be indispensable for carrying on an intelligent and responsible life.

在我看来，苏格拉底的信仰在明智而负责的生活中始终不可或缺。

youdao

Making things worse, he then goes on to say how important it is for all of us to become indispensable, for not to be indispensable is tantamount to economic and career suicide.

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The "Liberation Trilogy" will be an indispensable starting point for future writers about the U.S. Army in World War II.

WSJ: Book Review: The Guns at Last Light

It may be some time before the technique can routinely outperform a dog's nose, but may become indispensable for cases in which a grave may be hidden beneath more than just soil.

BBC: Hidden graves found using chemical 'sniffer' technology