单项选择题

By "his outdoor cousins" the author means ______.

A．other experimenters
B．B ) the other doves of the same brood
C．doves under the natural sky
D．other birds in general
<上一题 目录 下一题>
热门 试题

单项选择题
The experiment with the dove indicated that ______.
A．birds have to be taught to navigate
B．a bird that has been caged will not fly long distances
C．some birds cannot fly at night
D．some birds seem to follow the stars when they fly at night
单项选择题
The reason why birds don't get lost on long flights ______.
A．have been known to scientists for years
B．have only recently been discovered
C．are known by everyone
D．will probably remain a mystery
相关试题