chief
chief(主要的,最重要的:the chief reason = 主要原因;书面正式,通常作定语)
primary
primary(首要的,根本性的,书面:the primary objective = 首要目标;primary education = 基础教育;比 chief 更学术,强调「第一位的/根本的」)
The chief concern of parents surveyed was the quality of teaching rather than school facilities or academic results.
受访家长的主要关切是教学质量,而不是学校设施或学业成绩。
Access to clean water remains the primary challenge for communities in many arid regions of sub-Saharan Africa.
对撒哈拉以南非洲许多干旱地区的社区来说,获得洁净水仍是首要挑战。