VOA慢速英语:美国停飞所有波音 737 Max机型

analyze - v. to study (something) closely and carefully : to learn the nature and relationship of the parts of (something) by a close and careful examination

aircraft - n. a machine (such as an airplane or a helicopter) that flies through the air

refined - adj. improved to be more precise or exact

confidence - n. a feeling or belief that you can do something well or succeed at something

abundance - n. a large amount of something