Physics:What's That About — Bedtime Stories
The best way to avoid the dangers of sleep deprivation is to get a good night's sleep on a good mattress. Making a mattress is a complex process. When you go to buy mattress， you're not there to buy a mattress; you're really there to buy a good night of sleep. There are three parts of a mattress: comfort， support and durability. These three qualities start with the box spring.
- Added：2006
- Country：America
- Duration：60
- Time of update：2011/8/16 11:00:55