To clarify my question before,

I am diagramming sentences. When diagramming, verbs and gerunds go in very different spots. in the sentence Philip is planning a party, it could either be Philip | is \ (gerund goes a stand) planning | party. Or, it could be Philip |is planning| party. Many setences are like this. How can I always tell whether a word ending in ing is in progressive tense if it has a form of "to be" (is planning) or a gerund (is | planning).

Check this site :

http://www.jiskha.com/display.cgi?id=1205688517.1205690356

If Philip is planning a party.

If Philip and planning are identical...then planning would be a predicate nominative. Does Philip = planning... NOT likely. <G>
Is planning is what Philip is doing. Party is what Philip is doing it to. So party is the "object" of the planning...right?
Talking out loud to yourself is very helpful when doing grammar. Ask yourself questions...

The word "planning" is not a gerund in this sentence. It's the main verb, with "is" as it's auxiliary (helping) verb.

To determine whether a word ending in "ing" is in the progressive tense or is functioning as a gerund, you can follow these steps:

1. Identify the main verb: Look for the main verb in the sentence. In your example, the main verb is "planning."

2. Find the auxiliary verb: Look for auxiliary verbs (also known as helping verbs) like "is," "am," "are," "was," "were," "be," "been," or "being." In your example, the auxiliary verb is "is."

3. Analyze the function of the auxiliary verb: Determine if the auxiliary verb is helping the main verb create a progressive tense or if it is functioning independently.

- If the auxiliary verb is helping the main verb to create a progressive tense, it indicates an ongoing action. In this case, the word with "ing" is part of the verb phrase. For example, in "Philip is planning a party," "is planning" is the progressive tense indicating ongoing action.

- If the auxiliary verb is not helping the main verb create a progressive tense, it indicates a gerund. A gerund is a verb form that functions as a noun. It can act as a subject, object, or complement in a sentence. In this case, the word with "ing" is not part of the verb phrase but rather a standalone noun. For example, in "Philip is excited about planning a party," "planning" is a gerund acting as the object of the preposition "about."

In summary, if the word ending in "ing" is preceded by an auxiliary verb like "is," "am," or "are" and is helping create a progressive tense, it is functioning as part of the verb phrase. If there is no auxiliary verb, or if the auxiliary verb is not creating a progressive tense, the word ending in "ing" is functioning as a gerund.