My gloves have been missing for ages.

我的手套已经丢了很久了。

《牛津词典》

They have been missing for a long time now.

到现在他们已经失踪很长时间了。

《柯林斯英汉双解大词典》

The police are concerned for the safety of the 12-year-old boy who has been missing for three days.

那个12岁的男孩失踪三天了，警方对他的安全感到担忧。

《牛津词典》

"That is the ingredient which has been missing in far too many places, for far too long.

VOA: standard.2009.07.11

and it struck me that that there was a lot missing from the picture that has been given in Washington as they were trying to set policies that would affect education, that would affect the regulation of entertainment in terms of understanding of young people's relationships to technology.

让我感到震惊的是,在整件事情上还有许多东西不为人所知,在华盛顿这些都展示于世人面前,正如他们在制定政策,能够影响教育的发展，影响娱乐业的行业规则,至于了解,年轻人与技术的关系。

麻省理工公开课 - 媒体、教育、市场课程节选

What's really been missing is the right algorithm to connect the two components.

VOA: standard.2010.04.15

An Italian journalist has been missing in Syria for 20 days, his newspaper La Stampa says.

BBC: Veteran Italian war correspondent missing in Syria

Many missing persons who have been missing for a long time are still not found.

CNN: Missing persons could be just next door

"I've been kidnapped, and I've been missing for 10 years, " she told the dispatcher.

WSJ: Three Women Missing for Years Found Alive in Cleveland, Ohio