This question tests your understanding of gerunds and the correct grammatical structure after the preposition "of".

The sentence is: They were in danger of _____.

The word "of" is a preposition. In English grammar, a preposition must be followed by a noun, pronoun, or a gerund (a verb form ending in -ing that functions as a noun).

Let's analyze the options:

Option 1: to be injured - This is an infinitive ("to" + base verb). Infinitives cannot directly follow prepositions like "of".

Option 2: being injured - This is a gerund ("being") in the passive voice ("injured"). This is a noun phrase and is the correct form to follow a preposition.

Option 3: been injured - This is a past participle and cannot act as a noun to follow a preposition.

Option 4: injuring - This is a gerund, but it is in the active voice. The sentence structure "in danger of injuring" would mean they are the ones doing the injuring to someone else, which changes the intended meaning. The context suggests they are the ones at risk of being hurt.

Therefore, the most appropriate word to fill in the blank is "being injured".

Related Topics & Theory

Gerunds: A gerund is the -ing form of a verb that functions as a noun. It can be the subject or object of a verb, or the object of a preposition.

Prepositions: Words like 'of', 'in', 'at', 'on' that show a relationship between a noun (or pronoun) and other words in a sentence. They are followed by nouns, pronouns, or gerunds.

Key Formula/Concept

Preposition + Gerund

This is the standard grammatical structure. After a preposition, you need the noun-like form of a verb, which is the gerund.