What type of phrase is underlined in this sentence?

the train will be arriving in an hour or two.

the word in bold is the underline sentence!

Once you have finished revising your peer’s essay, continue to demonstrate your understanding of grammar and punctuation by writing an essay containing all of the grammatical concepts outlined above. your essay should be short, just 250 words, and it can be written on any subject. it should contain an example of parallel structure, an example of every type of phrase and clause outlined in this lesson, an example of two independent clauses connected by a semicolon, and an example of a colon. if you are struggling to come up with an idea for an essay, consider writing it about the themes present in one of the texts you have read already.