C15

Use a long dash to separate that main part of the sentence from a long interruption in the middle or a long appositive at the end.

General Principle

Incorrect Example

Correct Example

a) A writer may need to use a long dash to join a long appositive to the end of a sentence. 

She had had a narrow escape, an experience she would never forget. 

He stepped back and observed the result, a thing of beauty. 

She had had a narrow escape an experience she would never forget. 

He stepped back and observed the result a thing of beauty. 

b) A writer may use a long dash to separate the main parts of a sentence from an interruption to that sentence.

If everything material was taken away, electronics, toys, bikes, a child would not exist happily.

If everything material was taken away electronics, toys, bikes a child would not exist happily.