For the subway is an enduring _________ of mass-transit engineering: tains make 6,800 trips each day over 731 miles of rail, carrying 3.7 million people.
【简答题】Kate So the rules are... the boats follow each otherand the one behind has to bump the one in front... just like that one has done. Janet Is that Mark’s boat? Kate Yes! Look, his boat is about to bump...