阅读理解。 Squirrels often communicate with whistles, chirps and chucks, which sound like the word "chuck". Whistles and chirps are like the sounds that many birds make.Now scientists have translated some of their squirrel-speak. Hare, a professor of zoology at the University of Maniloha in Winnipeg, and his team managed to record squirrels' alarm calls.The researchers studied the sounds and then played them back to 60 wild squirrels, which the scientists approached individually with a video recorder to capture (抓拍) their reponses.Some squirrels lifted their heads up and became. Alert (警惕的).Creatures that were more frightened simply ran for their lives and dived into caves. "In effect then, whistles that mix with chucks say 'there's an enemy of average threat that's here', and whistles without chucks say 'there's an enemy of seemingly average threat around here somewhere', while pure chirps say, 'I'm hiding here because there's an immediate er.' " Hare told.Discovery News. Hare and some other researchers believe such sounds arc part of an advanced language that develops just as all other communication systems.Although squirrels risk their lives when they call out to warn others of threats, other squirrels might admire this behaviour, thus increasingly the caller's social status, like humans who look up to heroes. Hare added that other animals, such as birds, probably understand at least some squirrel language, since they also may benefit from the alarm calls. In fact, another Canadian study found that deep-voiced, black-capped chickadees have their own language too.According to certain research, there are a lot of tidings in chickadees' calls, such as directing fellows' activities, keeping in contact between mates, and raising alarms.While chickadees and other birds are often welcomed into gardens by homeowners, squirrels are frequently viewed as pests (害兽). Hare wishes a greater understanding of the complex social lives and communication systems of squirrels will provide "hope that humans will gain a greater appreciation and stop doing harm to these animals". 1.The text mainly talks about . A. the study on the language of squirrelsB. the comparison between squirrels and chickadeesC. the calling for the protection of squirrelsD. the ways for squirrels to escape from their enemies 2. If a squirrel is in a very erous situation, it would probably make ____. A. whistles with chucks B. pure chirpsC. whistles without chucks D. repeated chucks 3. The underlined word "tidings" in pardgmph 6 probably means ____. A. difficulties B. poises C. messages D. languages 4.What can be learned from this text? A. Squirrels communicate with cach other as humans do.B. Some squirrels understand the recorded alarm calls.C. Other animals also well understand the language of squirrels.D. Birds such as chickadees don't have their own language.