A.
1) Are you certain your mum’ll like this present?
2) Will it be cold tomorrow? — I’m not certain about it.
3) Would you like to play basketball with us today? - Certainly.
4) Do you think the film is good? — Sure.
5) I’m not sure that I’ll come here again.
6) Do you think Andrew will go to the restaurant with us? — I’m certain about it.
B.
1)
A: Will you stay with us for the weekend?
B: I’m not sure because my mum doesn’t feel well.
A: Oh, I’m sorry. I hope your mum will be better soon.
2)
A: Did Columbus discover America in 1492 or 1592?
B: In 1492, I think, but I am not certain about it.
A: Let’s find out.
3)
A: Victor speaks English and French, doesn’t he?
B: I’m sure that he does.
4)
A: Is Canada bigger or smaller than the USA?
B: I am not sure I don’t know geography very well.