Here's why:
* Participial Phrases: These are verb forms ending in -ing or -ed (or their past participle forms) acting as adjectives. Example: "Walking through the park, she noticed the flowers." (The participle "walking" modifies "she")
* Infinitive Phrases: These consist of "to" plus a verb. Example: "To travel the world is her dream." (The infinitive "to travel" functions as the subject)
* Gerund Phrases: These are verb forms ending in -ing acting as nouns. Example: "Swimming in the ocean is her favorite activity." (The gerund "swimming" is the subject)
All three types are verb phrases, meaning they are groups of words centered around a verb, but they function differently in a sentence.