When is it Appropriate to use Vibrato in music? What are some ways to practice without using Vibrato

In contour drawing crossing lines is one way to indicate this

Performer emphasizes a tone by playing it more loudly than the tones around it is called?

What poetic form do both montagu's and swift's poems use? a. both frequently use alliterative devices.b. both use quatrains as the stanza form.c. both use a free verse formatd. both use rhyming couplets.