1. Up front ①诚实的，坦诚的；②预先，提前
① You can count on her, for she is always up front with friends.
你可以信赖她，因为她对朋友总是很坦诚的。
② In order to hold your reservation, I need ＄100 as up-front cash.
为了保留你的预定，我要先收100美元的定金。
链接：
预先，提前：in advance
2. Up in the air 八字没一撇，悬而未决，还没确定
① The proposal of building a golf course next to the airport is still up in the air.
在机场旁建高尔夫球场的议案直到现在还悬而未决。
② - Are you dating Jenny now?
你跟詹妮开始约会了吗？
- It's up in the air.
八字还没一撇呢！
释义：字面意思是在空中，悬在空中，引申为悬而未决的，尚未决定的。
链接：
还没确定：
Anyone's guess. I haven't decided yet.
I haven't made my mind yet. We'll see.
