Periods, exclamation marks, and question marks are not used internally in sentences. Semicolons, colons, and commas are used externally in sentences.
<span> "The Secret Life of Walter Mitty" retreats into fantasy as an escape from his </span>mundane<span> reality. In the </span>real<span> world, he is </span>ordinary<span>, </span>passive<span>, and sometimes </span>inept<span>. </span>
Conflict is usually going to be the answer.
The sullen cat is as sad as an unfulfilled birthday wish.
The bear was a bulldozer through the brush.
The Black Plague clung to Europe for years.