The Colon is used to separate two parts of a sentence, when the first part is complete in itself, and the second part adds some statement relative to the first part in meaning.

You work ten or twelve hours a day: How can you find time to educate yourselves?

There are two worlds : The world we can measure with the line and rule, and the world we feel with our hearts and imagination.

# The Colon is now frequently used to introduce a quotation.

He looked at me, and remained silent, and then said in a low, husky voice: ‘My little daughter died last night. ’

# Sometimes a dash is written after a colon.

The three fountains of learning are :— Seeing much, suffering much, studying much.