形容詞 constructive:

1. constructing or tending to construct or improve or promote development
2. emphasizing what is laudable or hopeful or to the good

1. I can not figure out why they ridicule this constructive suggestion.
   我弄不懂他們?yōu)槭颤N嘲笑這一建設性建議。
2. It was regrettable that such great issues had to be the thrust and parry of a general election. But at least the debate should be constructive.
   如此重大的問題不得不成為大選中人們激烈辯論的議題，這很令人遺憾?？蛇@場辯論至少應該是建設性的。

con.struc.tive

adj.（形容詞）
Serving to improve or advance; helpful:
建設性的：起改進或提高作用的；有幫助的：
例句：
constructive criticism.
建設性的批評

Of or relating to construction; structural.
結構的：構筑的或與構筑有關的；結構上的
Law Based on an interpretation; not directly expressed.
【法律】 指定的：在解釋的基礎上的；未直接表達的

【引伸】
construc.tively
adv.（副詞）
construc.tiveness
n.（名詞）