单项选择题 A tide is called diurnal when（）.

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（）.