Unit 4 There is, There are

Countable nouns (Singular) 

Affirmative: There is a pear.

Interrogative: Is there a lemon in the fridge?

Negative: No, there isn't a lemon in the fridge

Countable nouns (Plural)

Uncountable nouns

Practice:

http://www.englishexercises.org/makeagame/viewgame.asp?id=2920

https://learnenglishkids.britishcouncil.org/en/grammar-games/nouns-countable-and-uncountable

http://www.macmillan.e-school.es/extras/Quest6/ws/level6_unit4_activity_3/index.html