VOA慢速英语:科学家称北极露脊鲸是北极的爵士歌手

filter - v. to pass (something, such as a gas or liquid) through a filter to remove something unwanted

vocalizations - n. to express (something) by speaking words

baleen - n. whalebone.

jazz - n. a type of American music with lively rhythms and melodies that are often made up by musicians as they play

microphone - n. a device into which people speak or sing in order to record their voices or to make them sound louder

motivated - adj. to have a lot of reason to do something

fingernails on a chalkboard - idiom. referring to an extremely annoying, unpleasant uncomfortably loud sound or noise.

variety - n. a number or collection of different things or people