副词出尔反尔，前进时帆忽张忽缩
1. (船顺流而下时)不断地调整船帆使船蜿蜒前进(以避开障碍 来来回回; 朝三暮四：back and edge 完全地; 全力地 | back and fill (船顺流而下时)不断地调整船帆使船蜿蜒前进(以避开障碍 来来回回; 朝三暮四 | back and forth 来回; 往复
2. 看风驶帆前进：back anchor 副锚 | back and fill 看风驶帆前进 | back and fill 看风驶帆前进;用左右抢风法前进
3. 在狭窄水道逆风顺流用左右抢风法前进：back and fill 看风驶帆前进;用左右抢风法前进 | back and fill 在狭窄水道逆风顺流用左右抢风法前进 | back and forth 来回
1. The sounds fill the front courtyard where visitors and tourists snap photos, echoing back towards the corners of the compound.