VOA慢速英语:研究表明太阳的活动性不如类似的恒星

rotation – n. turning in a circular direction

variability – n. the state of changing often

author – n. a writer of a book or report

view – n. the ability to see something or to be seen

parameter – n. a limit that controls the way something is done

geology – n. the study of rocks and soil and the physical structure of the Earth

boring – adj. not interesting

option – n. a choice or possibility

decade – n. a period of 10 years

standard – n. a level of quality or behavior