按课文填空。根据课文内容填入适当的单词，完成短文。（10分）

It’s also probably a good idea for parents to  _76 teenagers to study in groups  77 the evening. I know we get  78 sometimes, but we  79 a lot from each other. We also think that vacations should be   80 . At present they’re too short. Longer vacations would give us time to do things  81  volunteering. Last summer I had an  82 to volunteer at the local hospital, but I couldn’t because I had to  _84 back to school. It would be a good  _84 for me because I want to be a doctor when I’m  85  .