实义动词还可分为持续动词与瞬间动词, 前者可以与表示段时间的时间状语连用, 而后者不可. 但瞬间动词的否定式表示“该动作没有发生 , 可视为一种可持续的状态, 并可与段时间状语连用 a. They watched the train leave for five minutes. b. I received his letter yesterday. c. How long have you joined the army ?(错误: joined是瞬间动词, 不能与段时间how long连用) d. When did you join the army ? e. How long have you been in the army ? f. How long may I borrow the book ? (错误: borrow是瞬间动词, 不能与段时间how long连用) g. How long may I keep the book ? h. I haven’t received his letter for almost two months. (not receive表示“没有收到 , 这一意思可视为一种持续的状态, 因此可以和段时间two months连用) 【查看更多】
