单项选择题
A.only one high and one low water occur during a lunar day
B.the high tide is higher and the low tide is lower than usual
C.the high tide and low tide are exactly six hours apart
D.two high tides occur during a lunar day
单项选择题 A swift current occurring in a narrow passage connecting two large bodies of water which is produced by the continuously changing difference in height of tide at the two ends of the passage is called a(n)（）.
单项选择题 A strong，often violent，northerly wind occurring on the Pacific coast of Mexico，particularly during the colder months，is a（）.
单项选择题 A strong，often violent，northerly wind occurring on the Pacific coast of Mexico，particularly during the colder months，is called（）.