_______ good for our health.

 One-third of the area ________ covered with trees. About seventy percent of the trees _______ been planted recently.

Not only Jack but also his parents ________ the home accident.

We all feel it is Jack that _________ for their son’s bad performance at school.

Each of the students in our class　　　　great interest in English and we each　　　　a copy of A New English­Chinese Dictionary.