Answer:
is introduced in the final couplet
Step-by-step explanation:
In the first three quatrains of the Sonnet 73, Shakespeare provides the imagery of aging of the speaker. In the first quatrain, the speaker compares his age to the falling of the leaves. The second quatrain makes the speaker draw the imagery o twilight and compare it with that of his life. In the third quatrain the speaker draws a comparison of his life to the ashes left after the burning of fire. In the couplet, the speaker urges to grow love because the time to take part from the world would be soon arriving to him. The poet wants to emphasize more one love than the aging.