English and ESL Instructor
3) Incorrect — Addiction to video games is becoming a problem. (The subject pronoun for "addiction to video games" is "it".
4) Incorrect — A team of firefighters was trying to rescue the trapped persons. (The subject pronoun for "a team of firefighters" is "it".)
Now we will begin our lesson on adjectives and adverbs.
The function of both adjectives and adverbs is to describe. However, adjectives describe nouns while adverbs describe verbs, adjectives, or other adverbs:
Jill is a quick runner. ("Quick" is an adjective that describes the noun, "runner".)
Jill runs quickly. ("Quickly" is an adverb that describes the verb, "run".)
Jill is a very quick runner. ("Very" is an adverb that describes the adjective, "quick".)
Jill runs very quickly. ("Very is an adverb that describes the adverb, "quickly".)
As you probably noticed, "quickly" is another inflection of "quick". For many adjectives, adding the suffix "-ly" changes it into an adverb. When deciding which inflection to choose, it is important to look at what exactly you are trying to describe — a noun, verb, adjective, or another adverb.