不过，就像我曾经写过的那样，大多数人每天需要睡七到九个小时。
But as I have written, most people need seven to nine hours of sleep.
谷歌称其员工流失率七年未变，不过最近几次人员离职，显然令其不安。
Google says its attrition rate has not changed in seven years, but it has clearly been rattled by some of the most recent departures.
不过，这仍高于美国七倍，比英国高27倍。
But that is still seven times higher than America and 27 times higher than Britain.
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