You are never too careful.

你越仔细越好。

youdao

You are never too old to learn.

活到老，学到老。

youdao

You are never too big to stop learning.

你永远不会大到再也不需要学习了。

youdao

If you pick targets that are too hard or too risky, then you could end up never proving that your platform is worth anything.

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Some of the other versions, which I have never heard offered by the House managers, versions that maybe you, too, have never heard, are the ones that put the lie to the obstruction of justice allegation.

CNN: Transcript: White House Deputy Counsel Mills' statement

Toward that end you need people who are reliable in tight situations but you will likely never know that until it may be too late.

FORBES: Test of Leadership: Making the Tough Call