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TOEFL
/
Listening practice
/ Section TJD6
Listen to an Academic Talk
Listen to part of a talk in an astronomy class.
Listen
45. What produces the dark lines in a star's spectrum?
A
Dust between the star and the observer
B
Absorption by the cooler outer gas of the star
C
Gaps in the sensitivity of the instrument
D
Regions of the star's surface that emit no light