VOA慢速英语:教师们考虑不同的教学方式来教授语言和交际课

bubble – n. a tiny, round ball of air or gas inside a liquid; an object resembling a round ball of air or gas inside a liquid

engage in -- phrasal verb to do (something)

bizarre – adj. very unusual or strange

muffle – v. to decrease the noise made by (something)

distinguish – v. to notice or recognize a difference between people or things

specific – adj. special or particular

superhero – n. a fictional character who has amazing powers (such as the ability to fly)