而终止性的否定式就可以和表一段时间的状语连用，因为否定本身就是可以延续的。 如：have a cold是持续性动词，表示“状态”，可与表延续性的时间状语连用，不定冠词不能省略。
I′ve had a cold since my arrival.（到达 n.）
I didn′t go to school because I had had a bad cold for days.
catch a cold是短暂性动作，表“动态”：它不能和延续性时间状语连用，不定冠词“a”可有可无，catch可用take,get代替。 .
但是，若cold前有形容词修饰时，则不定冠词不能省。 如：Brown has taken a slight cold. 注意下列句子：
I have caught a cold for over a week.(×)
I have had a cold for over a week.( )
2、延续性动词：表示可以延续一段时间的动作或状态。如：be,drink,fly,eat,keep,lie,live,rain等。 延续性动词常不能和表示一个短暂具体的时间状语连用；这类动词如用于进行时态，则可以和表示一个短暂具体的时刻连用。
He worked at eight afternoon.(×)
yesterday
He was working at eight yesterday afternoon.( )
3、代替终止性动词的方法
a)用延续性动词代替终止性动词 1、用have代替buy
My brother has had(不能用has bought) this bike for almost four years. 2、用keep或have代替borrow I have kept(不能用have borrowed) the book for quite a few days. 3、用be替代become
How long has your sister been a
teacher?
4、用have a cold代替catch a cold Tom has had a cold since the day before yesterday.
5、用wear代替put on
b)用“be＋形容词”代终止性动词 1、be＋married代marry 2、be＋ill代fall (get) ill
3、be＋dead代die 4、be＋asleep代fall (get) asleep
5、be＋awake代wake/wake up 6、be＋gone代lose,die,sell,leave 7、be＋open代open 8、be closed代close/shut
9、be＋missing(gone,lost)代lose
c)用“be＋副词”代终止性动词 1“be＋on”代start,begin 2“be＋up”代get up
3“be＋back(to)”代return to,come back to,go back to 4“be here (there)”代come(arrive,reach,get) here
或
go
(arrive,reach,get) there等等
d)用“be＋介词短语”代终止性动词 1.“be in/at +地点”代替go to /come to 2.用be in the army 代替join the army 3.“be in/at +地点”代替move to