单项选择题
A stretch where the channel changes from one side of the river to the other is called a （）.
A.bifurcation B.transit C.crossing D.changeover
单项选择题 A storm’s track is characterized by all of the following except（）.
单项选择题 A stand-on vessel is（）.
单项选择题 A stage should only be rigged（）.
