<h2>
Answer:</h2>
(b) because she smiled at me
<h2>
Explanation:</h2>
Phrases are a group of words that are a part of a sentence and do not contain both a subject and a verb. In other words, a phrase does not contain a subject doing an action.
<u>Analyzing the given options:</u>
(a) <em>leaving behind the dog</em>
This group of words does not contain a subject even though it contains a verb - leaving. Therefore it is considered to be a phrase.
(b) <em>because she smiled at me</em>
This group of word among other things, contains a subject - a pronoun <em>she - </em>and a verb - smiled. Therefore, it is not considered to be a phrase.
(c) <em>smashing into a fence</em>
This group of words does not contain a subject even though it contains a verb - smashing. Therefore it is considered to be a phrase.
(d) <em>before the first test.</em>
This group of words neither contains a verb or a subject. Therefore it is considered to be a phrase.
(e)<em> pushing the sofa.</em>
This group of words does not contain a subject even though it contains a verb - pushing. Therefore it is considered to be a phrase.