A constructive discussion, comment, or approach is useful and helpful rather than negative and unhelpful.
例句
She welcomes constructive criticism...她欢迎建设性的批评。After their meeting, both men described the talks as frank, friendly and constructive...会面之后,两位男士均形容此次会谈坦率、友好且富有建设性。
英英词典释义
Adverb
1. in a constructive manner;
"it is my task to look critically and constructively at the flaws and the failures"