Documenting what the code is doing is common, but unnecessary.

注释代码当前做什么是很常见的，但这是不必要的。

youdao

Clear important, but unnecessary items off your schedule for a day - and let them go.

从你的工作日程中去掉那些重要但非必要的事，尝试一天，不要再想它们。

youdao

The concurrent collector introduced in Gingerbread helps, but unnecessary work should always be avoided.

Gingerbread中提到的并发回收也许有用，但不必要的工作应当被避免的。

youdao

But countries that are developed or growing quickly often have unnecessary surpluses.

VOA: special.2009.07.28

Galileo appears in the simile but actually seems to be unnecessary for the general purposes of the comparison.

伽利略在这个明喻中出现了，但明显他对于,这个对比的整体目的来讲是可有可无的。

耶鲁公开课 - 弥尔顿课程节选

which was so nice and so unnecessary, but she's wonderful.

真的很好，虽然没必要，但她真是太好了。

就业的方法 - SpeakingMax英语口语达人

That was magnanimous of Welker but unnecessary.

WSJ: Gisele's Super-Sized Super Gaffe

Aside from a humorous but unnecessary number that Kritzer sings to the toilet she's cleaning, Cooper is strikingly accurate and sensitive in her depiction of words and actions that will be familiar to anyone who's seen the effects of Alzheimer's disease in a friend or relative.

WSJ: Review: 'Memory Show' is poignant musical on loss

They also go a ways toward proving what we've long suspected: that handwriting is a neat, but often unnecessary, feature for most users.

ENGADGET: Sony Reader PRS-T2 review: same old e-reader, new and (mostly) improved design