托福讲座第三讲生物.ppt

新托福听力 讲座第三讲;讲座文段精讲单元二;讲座文段规律;动物学词汇;文本结构分析;习题;题解;题解;题解;题解;Now what’s interesting is that chaffinches are able to complete this process, even from only a short exposure to their parents’ song. Exposure during the first few weeks of life is really all they need, and after that they can remember it, even though they need quite a bit of practice to produce it accurately themselves. So the theory is that there is a sensitive period in the chaffinch’s early life, its early development, a special sensitive period during which it learns what its song should sound like. So chaffinches, um, along with many other birds, learn songs early in life, and when they become adults, they don’t change their songs—it’s a copy of the parents’ song, like we said, okay?;题解;题解; 谢谢!