单项选择题
A．he can see the difference between red and deep red B．he can see the difference between blue and green C．he can't tell the difference between orange and green D．he thinks green is the same as blue
A．was not famous 130 years ago B．is still famous now C．was famous 200 years ago D．is not famous now
A．The United States. B．Some persons loving birds. C．People who think of the birds. D．Audubon's future generation.