To learn Chinese well is difficult.(改为同义句) （It's）（ difficult）to learn Chinese well.
I didn't go to see a movie last weekend .(改为肯定句)
I （went）（to）see　a　movie　last　　weekend.
You　＇re　not　old　enough　to　go　school．（改为同义句）
You＇re　（too）　（young）　to　go　to　school