one or ones

I’ll have a piece of cake. Would you like to have _________too?

• one

• ones

A: Have you seen my new glasses?

B: You mean the _________ you bought last week?

• one

• ones

Let’s watch a different film. This _________ is so boring.

• one

• ones

This sentence is correct or not?

"New cars need less petrol than old one."

• correct

• incorrect

We have three children. The oldest ________ is 15 years old.

• one

• ones

Look at these trousers. _____________ do you like better?

• Which one

• Which ones

Your socks have holes. You should get new ones.

What does "ones" in the sentence refers to?

• new

• holes

• socks

A: Can you hand me my jacket, please?

B: Of course. _____________ is it?

• Which one

• Which ones

Jack has three pens – a red _______ and two green _________.

• one, one

• ones, ones

• one, ones

• ones, one

Small pineapples are sweeter than big ones.

What does "ones" in the sentence refers to ?