单项选择题

The water level of the oceans rises and falls ______.

A．often
B．often in a year
C．twice
D．twice a day
<上一题 目录 下一题>
热门 试题

单项选择题
The water level of an ocean falls ______.
A．when there is a low tide
B．when the water is pulled away from the earth
C．when the moon disappears over the horizon
D．when water no longer moves
单项选择题
The water level of an ocean rises ______.
A．when the moon is directly over the water
B．when the moon disappears over the horizon
C．when there is no tide
D．when there is a low tide
相关试题