1.wee hours 凌晨
Going to bed in the wee hours and snoozing until noon only disrupts the brain's clock further.
凌晨上床睡觉,一直睡到第二天中午,只会进一步破坏大脑的生物钟
2.too close to call 胜负难分
In the Senate, the count is too close to call at this point.
参议院现在的票数还难分上下
3.on the grounds that 基于……理由
The case was dismissed on the grounds that there was not enough evidence.
此案以缺乏足够的证据为由被驳回
4.hinge on 取决于……
Does not success or failure hinge on this?
成败之机,其在斯乎?