The given statement is an example of a phrase, specifically, a participial phrase. The element that is necessary to complete the sentence is an independent clause. A participial phrase consists of words with the -ing or -en form plus its modifiers. This kind of phrase always functions as an adjective. The phrase "Beginning in the fall of 1957" is describing a certain noun, which is found in the independent clause.
3rd one is the correct one
Ann is the subject of the sentence
has taught is the verb phrase
students is the direct object
junior high are adjectives that modify the direct object students
for several years is a prepositional phrase that modifies the verb taught
Answer:
grandpa is walking on the stairs very slowly
