VOA慢速英语:科学家观测到巨大星系团的诞生

cluster – n. a group of things or people that are close together

light-year(s) – n. a unit of distance equal to the distance that light travels in one year, about 9.46 trillion kilometers

galaxies – n. the very large groups of stars that make up the universe

journal – n. a magazine that reports on things of special interest to a particular group of people

author(s) – n. a person who has written something

in one fell swoop – idm. done all at once or all together

obvious – adj. easy to see or notice

flash in the pan – idm. a brief, intense effort that produces no really major result

mature – adj. grown to full size

evolve(d) – v. to change or develop slowly often into a better, more complex, or more advanced state