I've added yet another example for your perusal.
A subject
The word "not" is commonly used to make a sentence negative. For example, "I am happy" becomes "I am not happy" when "not" is added.
stopped
To make this sentence parallel, the verbs and subject must be in agreement. "Clean stalls" would be a phrase that would make this sentence parallel.
The flax was growing beautifully in the garden.
for an example:I added food coloring to the water to make it look pink
value added benefit
The singer's guttural growls added a powerful intensity to the metal music.
Paul added numerous parenthetical statements to his complicated instruction manual to make it easier to understand.
Beveled edges are a common aesthetic nicety added to window panes and mirrors. --Allyy.
Yes, though to make it flow more smoothly, I would write "I have sent an email requesting that you be added to the list."
After most verbs a completion is added. A completion is a set of words or a phrase that makes the meaning of the verb clear. For example, "The woman stopped", a completion is added to make the sentence make sense. "The woman stopped to take her hanky from her bag".