动物学家们做过一次有趣的实验:把一块肉用绳子悬在空中,绳子的一端系在树枝上鹦鹉想吃到肉,但不能停在半空中来夺肉.怎么办?一只鹦鹉经过多次扑腾均遭失败后,它不再直接扑向肉,而是抓起栓肉的绳子把它一段一段的提起,直到把肉提到自己的面前. The zoologists have done an interesting experiment: put a piece of meat in a rope and hang it in the air. One end of the string is tied to a branch. The parrot wants to eat meat, but it can’t stop in the air to gain meat. What to do? A parrot passes by After repeated defeats, it is no longer directly toward the flesh. Instead, it grabs the rope and lifts it up for a while, until it mentions the meat.