verb,noun,adj,adv的問題

reference can be used as adjective (e.g. reference material; reference search)

internationally is adv (e.g. this conference is held internationally)

attachment 附件 is noun (e.g. attachments to a reaping machine 收割機的配件)

active is adj, actively is adv, activate is verb but has different meaning of 使活動起來

dangerous is adj, danger is noun, there is no verb

compete is verb, competition is noun, competitive is adj, competitively is adv

practise can be verb or noun, there is no adverb. There are words similar such as practical/practically that are adj but have different meaning of 實際上;事實上