hours of sleep的用法和样例：
- I had nine blissful hours of sleep.
- Most people need six to eight hours of sleep every day.
- Let us snatch an hour of sleep .
- He felt chronically tired, requiring about 12 hours of sleep a day.
- I'd been existing on two or three hours of sleep a night.
- It's scientific fact: Bodies at play need eight hours of sleep to feel at rest.