Pls helped or im screwed beyond anything. What part of speech is the word "have," in the sentence "She must have been angry with him?"

Demonstrating understanding of jem's development one way to demonstrate understanding of character and theme is by writing from the perspective of a character. for this assignment, compose a short poem from the perspective of jem. your poem should detail his feelings about either a. his father, atticus or b. mrs. dubose. the poem must accurately trace the progression of jem's attitudes and beliefs, highlighting the important events and shifts in his perspective detailed above. your writing should also sound like jem, using voice and word choice that reflects the voice and word choice found in the novel. the poem can be a free poem (meaning it does not need to rhyme or follow a particular format). it should be a minimum of twenty-lines in length, have a title, and follow conventional rules of spelling, grammar, and punctuation.