THERE IS:HAY( singular or uncountable) Affirmative: There is a teacher in the class There’s water on the floor Negative: There is not a teacher in the class There isn’t water in the swimming pool Interrogative: Is there a teacher in the class? Is there water in the swimming pool? Answer: Yes, there is / No, there isn’t
THERE ARE:HAY(plural) Affirmative: There are 10 elephants at the zoo Negative: There aren’t animals at the zoo Interrogative: Are there whales at the zoo? Answer: Yes, there are / No, there aren’t