1. “三长”
(1) 介词短语
【定义】从介词开始到名词结束、表达一个独立的完整的含义的结构。
【起止标识】标记介词短语时，要从介词开始到介词之后的第一个名词终止。如：at home、in the school、in the beautiful park、during my happy childhood、over the last few years、for three weeks
【例句】 (After chatting) (with Laura) (on this matter) (for two hours) (from 2:00 to 4:00) (in the afternoon), I returned (to my office).
(2) 从句
【定义】从句是复合句中不能独立成句，但具有主语部分和谓语部分，由that、who、whom、when、why、where、how、which、if、although等关系词引导的非主句部分。
