单项选择题
A.Because an empire was set up. B.Because the empire fell to pieces. C.Because it lost its trees. D.Because too much had been spent on wars.
A.say B.describe C.mention D.write
A.planes fly higher than at the equator B.the eyes can reach about 4,000 meters C.planes are clear of bad weather D.planes fly more quickly than at the equator