useful compression ratio

例句：

1. 1.The new tool is very useful for the construction work.
   这个新工具对于建筑工作非常有用。
2. 2.The advice was very useful to me.
   那个建议对我非常有帮助。
3. 3. It's always useful to learn a new skill.
   学习一门新技能总是有益的。