改良者

例句：

1. 1.The scientist is a pioneer in the field of renewable energy.
   这位科学家是可再生能源领域的先驱。
2. 2. The company has been making significant improvements to its product line.
   该公司一直在其产品线上进行重大改进。
3. 3. The engineer was an innovator in developing new technologies.
   这位工程师在开发新技术方面是一位创新者。