line link frame

例句：

1. 1. The line of cars is moving slowly.
   汽车排成一行缓慢移动。
2. 2. She used a ruler to draw a straight line on the paper.
   她用直尺在纸上画了一条直线。
3. 3. The train is running on a single line.
   火车沿着一条线路运行。