改进者;改进物;学徒,练习生
Improver \Im*prov"er\, n. One who, or that which, improves.
improver n 1: someone devoted to the promotion of human welfare and to social reforms [syn: {humanitarian}, {do-gooder}] 2: a component that is added to something to improve it; "the addition of a bathroom was a major improvement"; "the addition of cinammon improved the flavor" [syn: {addition}, {add-on}]