Ⅰ．用所给单词的适当形式填空
【小题1】There are many ______（environment） problems in the world now．
【小题2】Every class collects______（reuse）waste．
【小题3】Do you care about______（protect）our earth?
【小题4】We must be ______（care）about the young trees．
【小题5】The old man has been seriously ill for a long time and will be______（hope）．