瞬间动词,也称为非延续性动词,是英语语法中的一个重要概念,尤其在中考英语中经常被考察。这类动词通常表示一个瞬间发生的动作,不具备持续性,因此它们不能直接与表示一段时间的状语(如for two months)连用。在完成时态中,瞬间动词的否定形式可以接一段时间,因为这表示动作没有发生在一个时间段内。
1. 瞬间动词不适用于进行时态。当它们以进行时态出现时,往往表示的是将来的动作,例如"I'm leaving for Hangzhou"(我正要去杭州),这里的"leaving"实际上意味着即将出发。
2. 瞬间动词不能与"How long"引导的疑问句搭配。例如,正确的问法应该是"How long is it since you left school?"(自从你离开学校有多久了?),而不是"How long have you left school?"。
3. 瞬间动词也不能与"for"引导的表示一段时间的状语连用。正确的表达方式应采用现在完成时态加上"since"或"ago",如"It is (has been) two months since he bought the computer."(他买这台电脑已经两个月了)。
4. 当瞬间动词与"until"引导的时间状语连用时,通常用否定形式,如"Don't get off the bus until it has stopped."(直到公交车停稳再下车)。
为了解决这些问题,我们可以采取以下替代办法:
a) 用延续性动词替换瞬间动词:
- "have"替换"buy",如"My brother has had this bike for almost four years."
- "keep"或"have"替换"borrow",如"I have kept the book for quite a few days."
- "be"替换"become",如"How long has your sister been a teacher?"
- "have a cold"替换"catch a cold",如"Tom has had a cold since the day before yesterday."
- "wear"替换"put on",如"He wears the new coat every day."
b) 使用"be+形容词"来替代:
- "be married"替换"marry"
- "be ill"替换"fall (get) ill"
- "be dead"替换"die"
- "be asleep"替换"fall (get) asleep"
- "be awake"替换"wake/wake up"
- "be gone"替换"lose, die, sell, leave"
- "be open"替换"open"
- "be closed"替换"close/shut"
- "be missing/gone/lost"替换"lose"
c) 使用"be+副词"来替代:
- "be on"替换"start, begin"
- "be up"替换"get up"
- "be back(to)"替换"return to, come back to, go back to"
- "be here (there)"替换"come(arrive, reach, get) here"或"go (arrive, reach, get) there"
d) 使用"be+介词短语"来替代:
- "be in/at +地点" 代替"go to /come to"
- "be in the army" 代替 "join the army"
- "be in/at +地点" 代替 "move to"
掌握这些替代方法对于正确使用瞬间动词至关重要,能够帮助避免在表达中出现语法错误,尤其是在描述持续性的状态或动作时。在学习英语时,熟悉这些规则和替换技巧有助于提高语言的准确性和流畅性。