The little boy entered the house,unhappy．His mother was__36__cakes in the kitchen．

The little boy entered the house,unhappy．His mother was__36__cakes in the kitchen．
She smiled as she__37__but stopped when she saw his face．”Tyler__38__ happened?Is．happen everything okay?” "Nothing is okay,Morn．”said the boy,” Today,in our science lesson,Mrs Green was talking about the__39__．She said that the whole world is getting dirtier and that many animals and plants are dying．She wants us to think of something we can do to help．I thought all the way全文