5- Infinitive phrase
Infinitive phrase: An infinitive phrase consists of an infinitive; it can function as a noun adjective or adverb.
e.g. To write clearly and concisely can be difficult sometimes. Infinitive phrase = functioning as a subject
e.g. Proofreading your writing is a good way to ensure the absence of typing mistakes. Infinitive phrase = adjective modifying ‘way'
e.g. To greatly increase the amount of stress in your life, leave your writing task until the night before it is due. Adverb modifying leave