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热心网友
它们有本质区别。
1. be动词,既可以是联系动词,也可以是助动词。
❶ 联系动词,后接名词、非谓语动词、形容词、数词、代词、副词、介词等作表语,且有各种时态变化:
一般现在时am\is\are\
一般过去时was\werer
完成时has\have\had\been
将来时用be原形
现在分词being
过去分词been
没有被动语态
He is a well-known artist.他是一位著名的艺术家。(名词)
The student has been here for hours.这个学生来这里好几个小时了。(副词)
My ambition is to become a scientist when I grow up.我的大志就是长大当科学家。(不定式)
When he was eleven, he graated from that school.他11岁时就从那所学校毕业了。(数词)
❷ 助动词,用于进行时和被动语态。
进行时:
现在进行时am\is\are+现在分词
过去进行时was\were+现在分词
将来进行时助动词+be+现在分词
完成进行时助动词+been+现在分词
He is reading now.他在看书。
I was doning my housework when he came.他来的时候我在做家务活。
He has been learning English ever since last year.从去年到现在他一直在学英语。
被动语态:
一般现在时am\is\are+过去分词
一般过去时was\were+过去分词
将来时助动词+be+过去分词
完成时助动词+been+过去分词
进行时只有现在进行时和过去进行时才有被动语态:
现在进行时am\is\are+being +过去分词
过去进行时was\were+being +过去分词
The room is cleaned every day.房子每天打扫。
He was criticized yesterday by his teacher.他昨天挨他老师批评了。
The building is being built now by the builders.建筑工人正在建这栋建筑物。
The machine has been fixed, working properly again.进去修好了,又在正常运转中。
2. do作为助动词,用于一般现在时的否定句、疑问句中,肯定陈述句不出现。有时也用于肯定陈述句中对谓语动词进行强调。祈使句中也用do表示强调或表示否定。一般现在时第三人称单数要用does形式。
He doesn't get up early every day.他每天起床不早。
Do you often go shopping after breakfast every morning? 你每天上午吃早饭后去购物吗?
Do sit down please.请坐!
Don't sit here doing nothing.别坐在这里无所事事。
He often does work hard every day.他每天的确努力工作。
热心网友
不能共存
有be动词的时候就能用be动词
如果是示意动词,在疑问和否定句中 ,就只能用助动词
热心网友
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