infrequent
infrequentadjective- not occurring often; rare
不经常发生的;偶有的;罕见的
her visits were so infrequent.
她不经常到访。
派生infrequencynouninfrequentlyadverb语源- mid 16th cent. (in the sense 'little used, seldom done, uncommon'): from Latin infrequent- from in- 'not' + frequent- 'frequent'
考试词汇表