单项选择题
Neap tides occur only（）.
A.at a new or full Moon B.when the Sun，Moon，and Earth are in line C.at approximately 28-day intervals D.when the Moon is at quadrature
单项选择题 Neap tides occur（）.
单项选择题 A wave entering（）is likely to produce bores．
单项选择题 （）is not a type of tide.
