Intonation refers to
a. speaking too quietly.
b. appropriate volume for a particular purpose.
c. that which a speaker is emphasizing through stress, volume and tone.
d. speaking too loudly.

sing because that is what they are doing in the sentence

explanation:

the simple predicate is the main verb in the predicate that tells what the subject does. example: my father fixed the dryer. read each sentence. draw a line under the complete predicate.