题目内容：

Buses leave Dorchester Station 20 minutes before and after every hour from 6：20am until 10:40pm .
A bus leaves Dorchester for St.Marks at___on Sundays.A 5:15pm B 4:00pm C 9:40pm D 11:40pm

优质解答

从早上六点二十到晚上十点四十分,每整点前后20分钟从道切斯特车站发一班车.