Here's the completed dialogue:
A: 'We're going to the beach tomorrow.'
(we / going / to go / beach / tomorrow)
Do you fancy going?
B: I'm not sure.
(I / not sure)
I want to stay at home and play computer games.
(I / want / stay at home and play computer games)
A: Come on, you'll enjoy it!
(come on, / you / enjoy)
It will be hot and sunny!
B: OK I'll think about it.
(OK / I think about)
**Explanation:**
1. **A's statement:** The first sentence already uses the suggested words to form a statement about going to the beach tomorrow. 'Do you fancy going?' is a way to invite someone.
2. **B's response (first blank):** The most appropriate phrase from the bracket is 'I'm not sure' as it expresses doubt about going.
3. **B's response (second blank):** Here, the sentence would express the reasons why B is unsure. Thus, the most suitable words are 'I want to stay at home and play computer games'.
4. **A's response:** The phrase 'Come on' is used to encourage the other person to join, and 'You'll enjoy it' is a way to convince them.
5. **B's final response:** 'OK, I'll think about it' shows that B is considering the offer.