The following sentence uses which principal part of the verb?

he is swimming in the deep end of the pool.

present
past
present participle
past participle

C) Present participle.

Explanation: present participle is the form of a verb, ending in -ing in English, which is used in forming continuous tenses (for example: he is eating), as a noun (for example: bad thinking), and as an adjective (for example: interesting facts). In the given sentence we can see an example of a present participle used to form a continuous tense: "he is swimming" so the correct answer is option C.

the answer is:

when will (v) the books (n) be (v) due?

nouns refer to people (other than pronouns), places and things, whereas verbs describe actions and are usually part of the predicate of a sentence. finally, pronouns can work as nouns and identify the participants in speech.

in the example sentence, "will" is a verb part or auxiliary verb, "be" is an infinitive verb and "books" is a plural noun.

the grass-plot before the jail, in prison lane, on a certain summer morning, not less than two centuries ago, was occupied by a pretty large number of the inhabitants of boston; all with their eyes intently fastened on the iron-clamped oaken door.

— the scarlet letter,

nathaniel hawthorne

''eyes intently fastened''

''iron-clamped oaken door''

are the answers