a toss-up 很难抉择的事

　　  It's a toss-up whether oil prices will go up or down over the days ahead.未来这些日子的油价涨落概率是一半对一半。

　　----Who do you think is going to win the big football game tomorrow?你觉得明天的大型足球赛谁会赢？

　　----Oh, I don't know. It's a toss-up, really.Orlando has a great offense, but Baltimore has a great defense.噢，不知道。这真的很难抉择啊。奥兰多队进攻很好，但巴尔的摩队防守也不赖。

　　 ‘Have you decided on the colour yet?’ ‘ It's a toss-up between the blue and the green.’ “你决定了要什么颜色没有？”“在蓝色和绿色之间实在难以取舍。”

　　bank on something信赖某事；指望;相信PHRASAL VERB If you bank on something happening, you expect it to happen and rely on it happening. 

　　Everyone is banking on an economic rebound to help ease the state's fiscal /ˈfɪskl/ problems. 每个人都指望经济反弹来帮助缓解国家的财政问题。

　　---Hey, I'm having a pizza party this Saturday. Why don't you come by?嘿，这周六我要办个披萨派对，你也来呗？

　　-----Oh, you can bank on that! I love pizza. I mean, love.噢，没问题！我爱披萨。我是说，超爱的。

　　in the dark 蒙在鼓里

　　How can you be so in the dark with this one?你怎么连这个都不知道呢？

　　Congress is largely in the dark about what the administration has been negotiating in the TPP.  关于政府正在讨论跨太平洋伙伴关系协定，国会大体上还蒙在鼓里。