一位姓张的听众想知道动词 “improve、enhance” 和 “promote” 的区别。动词 “improve” 和 “enhance” 虽然都可以表示 “让事物变得更好”，但 “improve” 暗示事物本身不完美或者有不足之处，所以需要通过改变而完善它，而 “enhance” 指 “让原本没有问题的事物 ...

A group standard for non-medical use disposable masks has been released, providing important technical support for quality supervision. It includes indexes such as color fastness, filtration ...