Peter : Are you sure air pollution is more dangerous for the children?
Jim : Yes, I'm quite sure. It causes the illness for them.
Anne : Are you sure all the garbage is easy to destroy?
Marry : No, I doubt about it. The garbage like plastics is difficult to destroy
Tamrin : Hey, don’t you know that we have a school bus now?
Firman : Are you certain?
Tamrin : Yes, of course. The headmaster himself told me.
Mini : I heard, our classroom will be renovated in the next view days.
Nur : Are you sure?
Mini : Well, I can’t tell you for sure. I think we should ask our teacher.
Jalal : What do you think we should give Arni as her birthday present?
Rusli : A doll, I think
Jalal : Are you sure?
Rusli : Yes, certainly. As far as I know, she likes doll.
Jalal : Well, it is possible I suppose, but I doubt it.
Rusli : So, what do you think?
Jalal : Why don’t we buy her a wristwatch?
Rusli : I don’t think so. It’s too expensive.
Jalal : You are right, but we can collect the money.
Rusli : Still, I doubt it. I’m broke now. I don’t think I can get enough moneywithin this week.
Jalal : Well, doubt isn’t going to do anything. I can lend you the money if you want.
Rusli : Really?
Jalal : Certainly.
Rusli : Thank you very much.
Jalal : Don’t mention it.