The moment class ended, the students headed for the canteen.
Tips
mistakes
Both readings are about motion, and what follows tells them apart. First-tone bēn is the running itself, with no destination attached: 奔跑 to run, 奔驰 to speed along. Fourth-tone bèn always has somewhere to get to: 直奔, 投奔, 各奔前程.
usage
With a number 奔 means closing in on that age. 奔三 is a fixed word for someone nearing thirty, and the pattern stretches to any round figure: 奔五十, pushing fifty.
Top 大, a person seen head-on with arms flung wide, and the indexing radical. It supplies the figure that moves. Under this reading the figure is not simply running: it is aimed at somewhere, and the sentence always names the destination.
Bottom 卉, three sprigs of grass, originally feet crossing open ground. It gives the compound its sense of covering distance. Nothing in the graph marks this reading, which is why only the tone separates 奔跑 from 直奔.
