D. parallel structure just means that all of your verbs in the comma series line up in regards to tenses, here. in choice D, it's "BE friendly," "INTRODUCE yourself," and "SMILE." these are all present tense verbs.
the rest of the choices don't match--"exercise" and "stretching" are two different verb forms in choice A, "to go to the library" is the odd one out in choice B, ane "to build" doesn't match with the "-ing" verbs in choice C.
<u>Answer:</u>
The singer was popular because he knew how to entertain the crowd.
Answer:
The idea is that it's hard but you'll be happy when you're done
Idiom "Hold your horses"
Simile "As red as a tomato"
Hyperbole "This food is hotter than the sun"
Metaphor "He was a walking encyclopedia"
Alliteration "Peter pepper picked a pickled pepper"
Personification "The sun smiled at me"
I hope it helped.
