Which sentence would you cite as an example of a gerund phrase functioning as a subject, illustrating a late-acquired structure in Krashen's framework?

• A. The son enjoys riding on the carabao
• B. He is reading a book
• C. They went to school
• D. She enjoys music

Answer: (B)

The key idea here is recognizing gerund phrases—forms built with an -ing verb that function as a noun—and noting that such structures are often acquired later by learners in Krashen’s framework. A gerund phrase can serve as the subject of a sentence when it acts like a noun.

Among the options, the one with the word reading paired with a direct object shows the -ing form in a way that aligns with a gerund use: reading a book. This is the form students encounter as a noun-like clause and is the kind of late-acquired -ing structure Krashen discusses. The other sentences either place an -ing form inside a verb phrase (is reading) or use the -ing form as part of a non-noun function (riding as the object of enjoy), not as a subject-like gerund phrase. So this option best illustrates the targeted gerund use.