我来回答吧!你可要给分啊!
1.there is和there are表示“有”这个状态,重在“存在”的意思.前者是接单数名词,后者接复数名词.注意：就近原则（就是单复数只看离它最近的一个名词）.
have和has表示从属的关系,意思是谁有什么什么.前者是一般式,后者是第三人称单数形式.
例：There are two apples in her hand.
She has two apples.
2.这个do是助动词,帮助动词提问.而be帮助名词等提问.
例：Is he doing his homework?
Does he do his homework?
3.情态动词后所有动词用原型.