利用实际生活中直线、射线和线段的图片，引导学生认识这三种类型的线，并自

The use of real-life lines, rays and segments of pictures, guide students to understand these three types of line, and compare their differences identifies the three types of lines <br>to guide students to explore independently based on real-life examples of custom wood, found that "two Point to determine the nature of a straight line

Use the pictures of straight lines, rays and line segments in real life to guide students to understand these three types of lines, and compare and summarize the differences of the three types of lines<br>According to the example of setting wooden strips in real life, guide students to explore independently and find the nature of "two points determine a straight line"

Use the pictures of lines, rays and line segments in real life to guide students to know these three types of lines, and compare and sum up their differences. Guide students to explore independently according to the examples of ordering wooden strips in real life, and discover the nature of "two points determine a straight line"