十几秒后绿灯亮了，两辆自行车一起过了马路，学校门口的保安也正好打开大门。
About ten seconds later the light turned green, the two bikes crossed the road together, and the security guard at the school gate opened the main entrance just in time.
About ten seconds later the light turned green, the two bikes crossed the road together, and the security guard at the school gate opened the main entrance just in time.