If you fall asleep easily but awaken several hours later, it may be due to low blood sugar.

如果你很容易睡着但在几个小时之后就会醒来，这可能是由于低血糖引起。

youdao

It could be costing you anywhere from 30 minutes to several hours a day in productivity. And that doesn't even count the potential for catastrophic failures.

那么你是非常合理的，那或许会耽误你每天30分钟甚至几个小时的生产力，而且那甚至无法避免潜在的灾难性的失败。

youdao

You will be under general anesthesia - asleep - during the operation which may last several hours.

手术会在全身麻醉下进行，所以病人在手术中持续几个小时是处于睡眠状态。

youdao

Keep in mind that a cross-country flight could subject you to several hours of pain.

CNN: Is it OK to fly after a head injury?

You had several hours of meetings here in the West Wing.

WHITEHOUSE: Press Briefing

Professional body builders consume up to 1.5 grams of protein per kilogram of weight each day, but unless you are spending several hours in the gym on a regular basis, this is too much for the average person trying to gain muscle.

CNN: How should I eat to build muscle mass?