Questions 21-24 Complete the summary below Choose ONE WORD ONLY from the passage for each answer Write your answers in boxes 2 1-24 on your answer sheet
原文
Much of the research my colleagues and l conduct uses homing pigeons, a species of bird that has been trained to find their way home from a long distance away. The pigeons in our study have been fitted with miniature tracking devices in individual backpacks that allow us to track and analyse their movements with incredible precision. Homing pigeons make good subjects because they are superb navigators and have been used for a variety of purposes over many hundreds of years of human history. Champion pigeons can be worth a fortune, Decades of research into their spatial cognition have revealed that their excellent navigation skills rely on a suite of senses: they use the sun and the earth's magnetic field as a compass, and they can build a mental map of their environment using major visual landmarks on their route as well as their ability to differentiate one smell from another.
Homing pigeons
第 21 题
Homing pigeons are superb navigators and have been useful to humans over many hundreds of years. They use the position of the _____ and their understanding of the earth's magnetic field like a ____ .They are also guided by important ____ and their well-developed sense of ____
正确答案：sun
第 22 题
Homing pigeons are superb navigators and have been useful to humans over many hundreds of years. They use the position of the ____ and their understanding of the earth's magnetic field like a _____ .They are also guided by important ____ and their well-developed sense of ____
正确答案：compass
第 23 题
Homing pigeons are superb navigators and have been useful to humans over many hundreds of years. They use the position of the ____ and their understanding of the earth's magnetic field like a ____ .They are also guided by important _____ and their well-developed sense of ____
正确答案：landmarks
第 24 题
Homing pigeons are superb navigators and have been useful to humans over many hundreds of years. They use the position of the ____ and their understanding of the earth's magnetic field like a ____ .They are also guided by important ____ and their well-developed sense of _____