You have by the verb phrase, am doing, described a progressive action, an action going on in the present.
In the following poem, mark every noun and every verb and verb phrase.
When we ask the question what millions do, our question is answered by the verb phrase, do live.
So the word bought is a part of the verb phrase, are bought.
Has diminished is the verb phrase, which is the simple predicate of this sentence.
When we use a verb phrase, it expresses some other time than the past or present.
The simple predicate is the verb or verb phrase without its modifiers.
The negative not very often separates the words forming a verb phrase.
We denote future time by use of a verb phrase made by placing shall or will before the simple form of the verb.
In this sentence, work is the subject of the sentence and will be commenced is the verb phrase.