a____ v. if two things alternate or you alternate them, they change from one tothe other in a repeated pattern( 使 ) 轮流; ( 使 ) 交替 a. happeningon one day, week, etc. but not on the day, week,etc. that immediatelyfollows 间隔的 n. aperson or thing that replaces another, and can act or be used instead ofthem 替换 ( 人 ) 物