Page 931 - Wordsmith A Guide to College Writing

Did you know that the bar code system used in retailing was
invented in 1970?

No question mark is used with an indirect question.

I wonder why Ursula always wears black.

Mr. Smith asked why the meeting was being held on Friday.

The Exclamation Point

Exclamation points are used to show extreme excitement or

surprise. They are seldom needed in a college essay. Unless you are

quoting someone who has just discovered that the building is on fire

(or has another reason for extreme excitement), there will be few
opportunities to use an exclamation point. Interjections such as

“Ouch!” and “Yikes!” are followed by exclamation points but are

seldom needed for college writing. So use exclamation points when

you quote someone who is shouting or speaking excitedly. Otherwise,

let your words, not your punctuation, convey the excitement of your
essay.

Informalexample Examples of Clumsy

versus Effective Use of Exclamation Points