单项选择题
Spring tides occur（）.
A.when the moon is new or full B.when the moon and sun have declination of the same name C.only when the moon and sun are on the same sides of the earth D.at the beginning of spring when the sun is over the equator
单项选择题 Spring tides occur（）.
单项选择题 Spring tides are tides that（）.
单项选择题 Set of current is（）.
