DO 1,实义动词。They do their homework enery day.
2,助动词,构成疑问和否定。They do not watch TV on Sundays.
BE 1.连系动词,后接名词,形容词,副词,介词短语等,构成:主+系+表结构。如:She is a student;. Mary and Lucy are beautiful.
2.助动词。构成现在进行时(be +V-ing) Look,he is watching TV.
BE (am,is,are)
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