Up in the air - 悬而未决、不确定、未知

对话1

Emily: Have you heard anything about our project deadline?

关于咱们项目的截止日期，你有听说什么吗

James: Not really. Everything is still up in the air since the manager hasn’t made a decision yet.

没有，啥都没定呢，因为经理还在考虑

对话2
Emma: Have you finalized your vacation plans yet?
你的度假计划敲定了吗？
Jake: Not yet. Everything is still up in the air because we're waiting to see if we can get time off from work.
还没有。啥都还没定，因为我们在等着看能否请到假。