Submitted by admin on Fri, 02/06/2015 - 22:34
definition:
A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
sentence:
There are reckoned to be about 400 billion stars in our galaxy, the Milky Way.
New planetary star systems and galaxies are being discovered almost daily.
difficulty:
easy
toefl frequency:
3
toefl classification: