I am sure (it) will be fine tomorrow 中的It 为什么不能用there替换?

I am sure (it) will be fine tomorrow 中的It 为什么不能用there替换? Will it be fine tomorrow?I'm not sure ,____ I am not sure if it will be fine or cloudy? "I hope that it will be fine tomorrow"中的“that”可以换成别的连词吗? tomorrow it be will fine 组成句子 It will be fine tomorrow ____ I'am sure it will be quiet useful是什么意思 用IF合并下列句子(1)It is possible that it will be fine tomorrow./I - It will be April 14 tomorrow?- Are you sure?I think it ___ It will be r___ tomorrow.There will be r___ tomorrow. will it be fine weather tomorrow?A i expect to B i think not A:i hope it will be fine tomorrow.B:______________ A.I hope