SENTENCE: The elephant is eating hay. 'is eating' is a present progressive according to my textbook. In my textbook, it says that a present progressive verb is made up of the present tense of the helping verb 'be' and the present participle of the main verb. What does this mean?

Excerpt from the trip of a lifetime elizabeth mohn 3 a little more than a week ago, my mother and father started packing our suitcases to prepare for our trip. my entire family woke up early sunday morning, packed the car, and began our expedition to niagara falls. when we reached the american-canadian border, i was excited to enter a foreign country for the first time. the third paragraph is mainly about a) traveling to niagara falls b) leaving the hotel. c) seeing the falls. d) returning home.