ballasting and sinking of mattress

例句：

1. 1.The new mattress has a unique design that makes it comfortable to sleep on.
   这款新床垫设计独特，睡在上面很舒服。
2. 2.The mattress is sinking in the middle, which is causing discomfort for the user.
   床垫中间下沉了，给用户带来了不适。
3. 3.Ballasting is essential for maintaining the stability of the mattress during transportation.
   在运输过程中，保持床垫的稳定性需要使用浮力。