Determine whether the underlined sentence opener in the sentence below begins with an adjective, adverb, infinitive, or prepositional phrase.
to satisfy his hunger, the giraffe munched on the trees.

The underlined sentence opener in the given sentence above is "To satisfy". This is an example of an infinitive. Infinitives can be formed with the words "to" plus the main verb. Infinitives can function as a noun, adjective and adverb. The infinitive in this sentence is used as an adjective, modifying the word "hunger". 

2. he asked me where was i going
3. i asked him what bought him there