We don't know the weather tomorrow=It ( )( )the weather tomo

We don't know the weather tomorrow
=It (is )(unknown )the weather tomorrow.
再问： If you keep doing ( ) this for a long time,you are sure have great ( ) in your study.
再答： If you keep doing ( on ) this for a long time,you are sure to(貌似少了to) have great ( progress/improvement) in your study. 还有前面那个is unknown感觉不大对 还是用depends on比较好 采纳哦