1 Is there
由a white sheep可知,谓语动词为单数形势,且为问句
2 There are
由some sheep可知,谓语动词为复数 sheep单复同形
3 has
由a dog可知,谓语动词为单数形势
4 have
由teachers可知,谓语动词为复数
5 There is
由water可知,谓语动词为单数形式 water为不可数名词
不可数名词的谓语动词用单数
6 Are there
由trees可知,谓语动词为复数形式,且为问句
7 has
由主语a girl可知,谓语动词为单数形式
8 ……该句有问题吧
应该是 Does Tom have many apples?Yes,he does.