be up in the air

基本解释

But if Qaddafi should fall, the fate of the country's vast oil wealth would be up in the air.
不过如果卡扎菲真的下台了，那么利比亚的大量石油资产的命运将何去何从，还是未知之数。
Your emotional life may be up in the air if your mate has been going through a change of heart.
若伴侣的想法有所改变，感情生活将会处于一种悬而未决的状态。
I believe I would enjoy this because I would meet people from all over the world, be up in the air where I love to be, and have an independent lifestyle in paradise.
我乐在其中，因为我可以在这个过程中遇到世界上形形色色的人。我喜欢在蓝天翱翔的感觉，享受这样独立自在的生活方式。

That means, if you are going in a plane and you throw something up in the air, it seems to be going up and down to you.
也就是说,如果你在飞机中,你向空中扔出一物体,它也许会相对于你上下运动
耶鲁公开课 - 基础物理课程节选

While Russia may be up in the air, Wal-Mart confirmed its increased investment in China this past weekend.
FORBES: Wal-Mart Expanding In China, Possibly Returning To Russia
The aircraft isn't complete quite yet, but barring unforeseen obstacles, like a run-in with a giant needle, it should be up in the air starting October 15th.
ENGADGET: US Air Force enlists super blimp for Blue Devil surveillance initiative
Okay, so this week it all seems to be a bit up in the air, so to speak, and it continues -- in a round about manner -- with this story relating to a redesign of the NASA logo.
ENGADGET: Alt-week 7.21.12: Outer space, flying hotels and federal trolls