To keep a date, such as june 15, from being separated between lines of a document, where the word june might display on one line, with 15 on the next, you could:
If you want to type a date like June 15 and always make them appear together even at the end of the line or line change you should put a non breaking space between June and 15. This can be done by pressing ctrl and shift keys at the same while pressing spacebar.
