一 Do you know how the guide dogs help the blind?

一 Yes, they can         the blind to         they want to go.

Dear Pet,
   Without knowing more about you, it's hard for me to give you some good advice.
   But first, I am sure that you are1 . You said that nobody would care if you left home. What about your2?  And other family members? It seems that you are very3 . You'd better go to a doctor or talk 4 your parents. They will be able to help you.
Second, I'm sure there’s someone else in your class who feels lonely, 5. You never know6other people feel. Try to make friends with your classmates. And you could7a club to meet new people and make friends, too.
   You8find happiness in yourself. So my9advice is to write a list of all the good things about yourself, learn to like yourself, and then10 will see your confidence (信心)and like you, too.
                                                                                                                                                                                  Editor

0.191919是循环小数。

我们学习了O₂、CO₂、H₂这三种气体的性质．某小组同学用图所示装置成功干燥并收集了某纯净气体，甲、乙、丙三位同学对该气体的组成有不同的认识，甲认为可能是O₂，乙认为可能是CO₂，丙认为可能是H₂．你认为他们之中____推测是正确的，并说明理由____．

民以食为天”，我们青少年正是长身体的关键时期，要注意营养的均衡补充。下列有关健康叙述正确的是(    )
①正常人每天去都应摄入一定量的蛋白质②油脂会使人发胖，故禁食油脂③维生素有20多种，多数在人体内不能合成，需要从食物中摄取，饮食中要注意补充水果等含维生素较多的食品④青少年正处于生长发育阶段，需要多摄入钙，成年人体格已经健全．可以不补充钙。