什么是现在完成时中的延续性动词

延续性动词延续性动词表示的动作不但可以延续,而且可以产生持久的影响。常见的这类动词有：be,have,keep,know,learn,lie,live,read,sing,sleep,stand,stay,wait,walk,watch等。延续性动词的用法很广,但常见于现在完成时中的句子中,且常与for,how,long,since等引导的表示一段时间的状语或状语从句连用。例如：1．I have learned more than 1,000 Chinese words since I came to China．自从来到中国,我已经学会了l,000多个汉字。2．We have lived in Linqing since we came here．自从来到这儿,我们就一直住在临清。3．I have kept the picture for about three years．这张画我保存了大约三年。