I love it when someone points at the few miistaaaakkes in your fabulous work. And that weird person has never ever uploaded a single thing. That's a bit why i stopped here. Moreover have no students myself. Chapeau dear friend.
I found a few mistakes in good answers. 1) Opposite of happy is sad, not sadf. 2) Opposite of open might also be closed, not only close, if we talk about adjectives and not verbs. 3) Opposite of rich is definitely poor, not pooor with 3 "o´s". 4) Opposites of nervous and angry might also be calm. So due to these mistakes I consider this worksheet completely useless.