168.on hearing the song 一听到这首歌
169.have difficulty in doing… 做……有困难
170.catch the train/catch up with/be caught in the rain 赶赶火车/赶上/淋了雨
171.get on/off the bus/train 上/下公共汽车/火车
172.The teacher, with/together with/along with/as well as his students, is climbing the Fragrant Hill. 主谓一致的非就近原则