这是我见过最干净的实验室。

This is the ___cleanest laboratory I've ever visited.

在所有候选人中，他是品德最高尚的一个。

Among all the candidates, he has the ___cleanest character.

这份报告是部门里错误最少的。

This report is the ___cleanest one in the department.

这种太阳能发电系统是当地最环保的能源解决方案。

This solar power system is the ___cleanest energy solution in the area.