適切な派生語・反意語を文中に入れる問題[初級/中級/上級]

[Q24/中級] (  )に入る派生語は？

A competitive market helps to promote (▷efficient(効率的な)の名詞形).





A competitive market helps to promote efficiency. 競争的な市場は効率性を促進させるのに役立つ。
A: efficiency