a toss up的用法和样例：
- The election is a toss up, the winner still have not is determined.
- It's a toss up between them, I really don't know who would win.
- Let's toss up a penny for the chance to go first.
- It's a toss up, I think.
- A toss of a coin decided who should play first.
- toss up a coin做猜钱币反正面的赌博...
a toss up的相关资料：