primary element 的近义词 21 个

• foundation
• infrastructure
• source
• authority
• backbone
• basis
• core
• essence
• essential
• evidence
• fundamental
• groundwork
• heart
• key
• origin
• principal
• principle
• root
• underpinning
• chief constituent
• important part

primary element 的反义词 9 个

• auxiliary
• exterior
• exteriority
• outside
• surface
• trivia
• annex
• branch
• top