1·For less than half an hour, all battery-powered boats in Inner West Lake and man-powered boat on Outer West Lake returned. Those boats that are far from the dock were tugged by towboat .
不到半小时，里西湖内的电瓶船全部召回码头，外西湖上的自划船也全部返回，离岸较远的则由拖船拖回。
2·For example, permits could be issued to travel through locks at specified times, and those permits could be traded among towboat captains.
比如，可以通过许可证的发放将船闸通行限定在指定时间内，而且许可证也可以在拖船船长之间进行交易。