VOA慢速英语:科学家首次测量蓝鲸的心率

electrocardiogram – n. a machine that detects and records the electrical activity of the heart

mammal – n. a type of animal that feeds milk to its young and that usually has hair or fur covering most of its skin

diet – n. the food that a person or animal usually eats

flipper – n. one of two flat body parts that stick out from the side of a seal, whale, etc., and are used by the animal for swimming

fascinate – v. to cause (someone) to be very interested in something or someone