It is well-known that man is much c_________than any animal. But which is the cleverest a________ the animals? Some scientists t________ it should be Alex, an African grey parrot. He is unlike any other animal. He can really t________ with people! When he says “come here”, he really w_____someone to come up to him.”  “Alex is as clever as a c_______of 2 or 3 years old,” says Dr. Pepperberg. “He does not just repeat（重复） the sounds he has been taught. He understands the w___”
Alex can tell about 50 d_______things, name 7 colours and count f_______1 to 6. “Is the parrot actually thinking in the way how man does? ”Nobody can say. But the q_______ is very interesting.