One piece is missing.

我少了一件行李。

youdao

One important piece is missing: the business data, which is the life blood of every application.

这里还缺少一个重要的部分：业务数据，这是所有应用程序的血液。

youdao

To the Chinese who expect so much from this film, Astro Boy is more like a jigsaw puzzle with one piece missing –there`s a feeling of deja vu, but you know something is wrong.

对于那些期望颇高的中国观众来说，《阿童木》更像是一副残缺的拼图——尽管感觉上似曾相识，但总觉得有些别扭。

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One piece the government is missing, is Raj Rajaratnam, who could provide testimony saying what specifically went down with Mr. Gupta.

FORBES: Rajat Gupta Trial Will Be Government's Test of Mosaic Theory

There is one missing piece of the jigsaw.

BBC: The beginnings of 'financial repression'?

In essence, elites are always missing one vital piece of information: what it is like to be someone who is not in the elite.

FORBES: Why Some Elites Know Not What They Run