防火、灭火、自救等安全知识是每个人都应该了解的生活常识．下列做法错误的是（　　）

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在两条平行线之间画几条与平行线垂直的线段．

量一量这些线段的长度，你有什么发现？

我国实行民族区域自治制度的前提是（    ）

下列关于光的波粒二象性的说法中，正确的是（   ）

    My name is Sam. I am a junior high school student. My school is close to my home, so I always go to school on foot. Classes start at 8 a.m., and I am seldom late. I like Geography best. I enjoy learning about different places in the world.

    In the morning, we usually study Chinese, Maths and English. We have our morning break at 9:50 a.m..  When the bell rings, I run to the playground with my best friends Tom and Jack. We often play games. Break ends at 10:10 a.m..

Lunch is from 11:50 a.m. to 12:30 p.m.. Afternoon classes end at 3:30 p.m. Then Tom, Jack and I take part in the school bank practice. We make great music together.

    I always have a good time at school.