sentences: the new moon is when the dark half of the moon faces the earth & the dark half of the moon is not visible ->  new moon is when the moon cannot be seen  new moon is when the moon cannot be seen & a new moon is a kind of phase of the moon & a student cannot observe the moon in the clear night sky on feburary 21 ->  the student observes a new moon phase on feburary 21  the student observes a new moon phase on feburary 21 & a moon phase occurs 28 days after the last time it occurred ->  the next new moon will occur 28 days after feburary 21  the next new moon will occur 28 days after feburary 21 & 28 days after feburary 21 is march 21 -> the next new moon will occur on march 21