Key points
I'm sure you can find lots of information on theInternet now.
be sure ( that )+句子确信……;肯定…I'm not sure if that is a good idea.
be not sure if/whether+句子不确定……是否……Eg:我确信他会来参加我的生日晚会。
lam sure ( that ) he will come to my birthday party.他不确定他是否去我的生日晚会。
He is not sure if/whether _ he will go to my birthdayparty.