out用作副词最基本的意思是“出,在外”,在此基础上引申出多种意思,并可与许多动词搭配使用,构成习语; 在句中可用作状语、表语; 与of连用可构成复合介词。
out用作副词的用法例句:
His book came out last month.他的书上个月出版了。
He took out a book from the case.他从箱子里拿出一本书。
Students may not stay out after midnight.学生午夜后不得在外逗留。
落后:fall behind
落后:lag behind