保存已发出消息

例句：

1. 1. We need to save water for the plants in the garden.
   我们需要为花园里的植物节省水。
2. 2. The scientist saved the last drop of oil from the spill.
   科学家从溢出的油中挽救了最后一滴油。
3. 3. She saved a lot of money by taking advantage of discounts.
   她利用折扣节省了很多钱。