通常情况下，船舶空载航行时，其吃水差与船长之比应（）。
A．大于2.5%
B．大于1.5%
C．小于2.5%
D．小于1.5%
参考答案：C
观察一个正方体，最多能同时看到它的______个面．
The satellites over the major ocean regions cover the globe（）.
A.besides the polar regions
B.including the North Pole and the South Pole
C.above 70°N and below 70°S
D.as for north and south as 70°
