Grammar | There is / are

• (+) There's a banana. (There is)
• (?) Is there a banana?
• (-) There isn't a banana.

• (+) There are two bananas.
• (?) Are there two bananas?
• (-) There aren't two bananas.

• (+) There are some bananas.
  (/many / a lot / few / a few)
• (?) Are there any bananas?
• (-) There aren't any bananas.
   

BUT, uncountable
 

• (+) There is some milk.
  (a lot of / little / a little)
• (?) is there any milk?
• (-) There isn't any milk

Grammar | Countable or Uncountable?