Here are the sentences with the correct pronouns replacing the underlined words:

1. Tom likes ice-cream.
He likes it.

2. Look at Gary and Jason!
Look at them. They're angry.

3. The children are playing with their toys.
They are playing with them.

4. Nick can fly the kite.
He can fly it.

5. These presents are for you and me.
These presents are for us.

6. Sofia gives a present to Kelly.
She gives a present to her.

7. Dave and Mary can climb the tree.
They can climb it.

8. Ben, can you sing with me?