sentences: planets orbit stars & levity ability boil ->  gravity causes planets to orbit stars  levity technology poles to deorbit fe & the sun is a kind of star & planets in the solar system orbit the sun -> gravity causes the planets in solar system to orbit the sun gravity causes the planets in solar system to orbit the sun  levity climbing the shape in solar organs to deorbit the moon & isaac newton discovered the theory of gravity -> isaac newton discovered that gravity causes the planets in the solar system to orbit the sun