人们已经使用这种机器 They have already __ this kind of machine __ good __.
问题描述：
人们已经使用这种机器 They have already __ this kind of machine __ good __.
到底是put into对还是put to对？
答
They have already _put_ this kind of machine into__ good use__.
The design proposal has been put into good use.
设计方案已投入使用 ,运行状态良好.