题目内容
Why don’t birds get lost on their long flights from one place to another Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blanks. Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly by night Tests with artificial stars have proved that certain night - flying birds are able to follow the stars in their long- distance flights. A dove (鸽子)had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky. (76) The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight. (77) But the stars are apparently their principal means of navigation(航行)only. When the stars are hidden by clouds, they seemingly find their way by such landmarks as mountain ranges, coast lines, and river courses. But when it’s too dark to see these, the doves circle helplessly, unable to find their way. The reason why birds don’t get lost on long flights ______.
查看答案
搜索结果不匹配？点我反馈
更多问题
You probably won’t be shocked to find out that the inventor of tire rubber is Charles Goodyear, as he’s the only guy on the list to actually get his name attached to the end product. (46) It wasn’t easy coming up with a form of rubber tough enough to withstand the drag racing and car chases everyone envisioned the day the automobile was invented. In fact, if there was one man who should have given up his life dream, it was Goodyear. (47)The man spent time in and out of prison, lost every friend he had and starved his children in his tireless pursuit of a stronger form of rubber.(48) After his first two years of tinkering and failing with primitive rubber in the 1830s, Goodyear and his family were camping out in an abandoned factory and fishing for sustenance. This is when he made a huge breakthrough: He’d use acid to smooth out and toughen rubber! The government bought 150 mailbags made of the stuff and the rest is...Oh, wait. They were all defective. The process didn’t work and Goodyear was ruined. Again.Finally in 1839, Goodyear wandered into a general store with another failure of a formula. The crowd watched and laughed at him. (49)In a rage, he began to shake his fist, flinging a piece of his rubber onto the hot stove top.After inspecting the charred remains, he realized that he had just found a way to make durable, weatherproof rubber. (50) Despite what we’re sure were numerous failed "now let’s try setting this on fire to see if it improves it!" experiments, an empire was born. (50) Despite what we’re sure were numerous failed "now let’s try setting this on fire to see if it improves it!" experiments, an empire was born.
Analysts have their go at humor, and I have read some of this interpretative literature, (1) without being greatly instructed. Humor can be (2) , (3) a frog can, but the thing dies in the process and the innards are (4) to any but the pure scientific mind.One of the things (5) said about humorists is that they are really very sad ’people clowns with a breaking heart. There is some truth in it, but it is badly (6) . It would be more (7) , I think, to say that there is a deep vein of melancholy running through everyone’s life and that the humorist, perhaps more (8) of it than some others, compensates for it actively and (9) Humorists fatten on troubles. They have always made trouble (10) They struggle along with a good will and endure pain (11) , knowing how well it will (12) them in the sweet by and by. You find them wrestling with foreign languages, fighting folding ironing hoards and’ swollen drainpipes, suffering the terrible (13) of tight boots. They pour out their sorrows profitably, in a (14) of what is not quite fiction nor quite fact either. Beneath the sparking surface of these dilemmas flows the strong (15) of human woe.Practically everyone is a manic depressive of sorts, with his up moments and his down moments, and you certainly don’t have to be a humorist to (16) the sadness of situation and mood. But there is often a rather fine line between laughing and crying, and if a humorous piece of writing brings a person to the point (17) his emotional responses are untrustworthy and seem likely to break over into the opposite realm, it is (18) humor, like poetry, has an extra content, it plays (19) to the big hot fire which is Truth, and sometimes the reader feels the (20) . 17（）
Why don’t birds get lost on their long flights from one place to another Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blanks. Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly by night Tests with artificial stars have proved that certain night - flying birds are able to follow the stars in their long- distance flights. A dove (鸽子)had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky. (76) The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight. (77) But the stars are apparently their principal means of navigation(航行)only. When the stars are hidden by clouds, they seemingly find their way by such landmarks as mountain ranges, coast lines, and river courses. But when it’s too dark to see these, the doves circle helplessly, unable to find their way. In total darkness, doves
A group of people who share the same interests and way of life is called a society. Sociology is the science that examines human society. The term sociology is derived from the Latin word socius, which means "companion, union of people". (80) Sociologists are interested in how a society began and how it grew. They also study the levels within a society. For example, the child is part of the family, the family is part of the neighborhood, and the neighborhood is part of the community. There are many different groups, and sociologists are interested in the effect that these groups have on people. A Frenchman named Auguste Comte made sociology a separate science in the l’830s. He suggested that a new science was necessary to study a society of people. A famous book, Principles of Sociology, was published by an Englishman, Herbert Spencer, in 1882. This book had an unprecedented(史无前例的) effect on the science of sociology. In this book, Spencer theorized that a society’s customs evolved, or grew, from very simple to more complicated and advanced. This theory shows the influence that Charles Darwin (who believed that man had evoked from very simple forms to the present human) had on Spencer. What is the best title for this passage
微信支付 
支付宝支付