One way to describe the subject of a sentence is to use an infinitive gerund article preposition

One way to describe the subject of a sentence is to use an  infinitive.

Explanation: Gerunds are nouns. They don't describe nouns because they, themselves are nouns. A gerund is a verb that becomes a noun by adding "ing", e.g. Reading is awesome. Articles go before nouns but they aren't used to describe nouns. Prepositions indicate position or place mainly. An infinitive is a verbal that can function as noun, adjective, or adverb. It is formed by using "to" + the verb.

7

explanation:

it depends on what grade.

kindergarten to senior year in high school will go for about 7 hours. pre-k will go for bout 4-5 hours. college, it depends on your classes.