社会失范
参考答案：
凡是存在着不明确的、彼此冲突和分散的规范的地方，个人与他人就不存在有道德意义的关系，或者没有规定获得快乐的界限，这就是社会失范。
根据语境，填写适当的词语或句子补全对话。
A: Hi, Tom. Why 1. _ you do PE today?
B: I have broken my arm.
A: 2. _ did you do that?
B: I fell off my bike.
A: Sorry to hear that. 3. _?
B: Yes. I went to the clinic yesterday, and the X-ray showed that my arm was not serious.
A: OK. Why do you 4. _?
B: Because I'm afraid I'll miss more lessons and I'll be left behind.
A: Don't worry. Just take care of yourself. I think I can 5. _ you.
B: Thank you.
普通螺纹牙顶应是______。
A．圆弧型
B．尖型
C．削平的
