【简答题】阅读理解。 When a cat is frightened, its heart starts beating faster, its muscles get tense, and there are changes in the chemicals in its blood stream. If the er continues, it will defend itself, or i...
【单选题】听力原文: Man has a big brain. He can think and speak. Scientists used to think that men are different from animals because they can think and learn. They now know that animals can learn —dogs, rats, bird...