Hyphen Usage

How well do you know hyphen rules?  Check this out:

Some strong examples of semantic changes caused by the placement of hyphens:

• Disease-causing poor nutrition, meaning poor nutrition that causes disease
• Disease causing poor nutrition, meaning a disease that causes poor nutrition

• A man-eating shark is a shark that eats humans.
• A man eating shark is a man who is eating shark meat.

• A blue-green sea is a sea whose color is somewhere between blue and green.
• A blue green sea is a contradiction, unless "blue" or "green" are used contextually to mean something other than a color.

• Three-hundred-year-old trees are an indeterminate number of trees that are 300 years old.
• Three hundred-year-old trees are three trees that are 100 years old.
• Three hundred year-old trees are 300 trees that are 1 year old.

For more hyphen rules (and other grammar rules), check out:

http://www.grammarbook.com/punctuation/hyphens.asp