英语听力精选进阶版 13692（在线收听）

Citizen scientists

 Vocabulary

evidence

facts that make you believe something is true

extraterrestrial intelligence

advanced life forms existing beyond our planet

clues

pieces of evidence

analyse

examine

volunteers

people who do something without being paid for it

vital

essential

age-old

long-standing or very old

astronomers

people who study space

citizen

person belonging to a particular country

tantalizing

exciting, making you want more (even if it is not possible)

exists

occurs