This question tests your understanding of gerunds and passive voice in English grammar. The sentence structure is "I am against children _____ to school...".

The word "against" is a preposition. A fundamental rule is that a preposition must be followed by a noun, a pronoun, or a gerund (a verb form ending in -ing that functions as a noun). This immediately eliminates options that are infinitives ("to be sent", "to be sending").

Now, let's analyze the meaning. The subject of the blank is "children". The action is "send to school". In this context, the children are not doing the sending; they are receiving the action. They are the ones being sent. Therefore, we need the passive voice.

A gerund in the passive voice is formed by "being + past participle".

Let's evaluate the options:

• to be sent: This is an infinitive in the passive voice. It cannot follow a preposition like "against".
• having been sent: This is a perfect gerund in the passive voice. It describes an action completed in the past. The sentence is about a general opinion against a practice, not an action that has already happened.
• to be sending: This is an infinitive in the active voice, meaning the children are doing the sending. This does not make logical sense.
• being sent: This is a gerund in the passive voice. It correctly follows the preposition "against" and conveys that the children are the recipients of the action.

Step-by-step solution:

Step 1: Identify that the blank follows the preposition "against". A gerund (-ing form) is required.

Step 2: Determine if the verb should be active or passive. The children are not sending themselves; they are being sent. Passive voice is required.

Step 3: The correct structure for a passive gerund is "being + past participle".

Final Answer: The most appropriate word to fill in the blank is being sent.

Related Topics & Formulae

Gerunds: A gerund is a verb form that ends in -ing and functions as a noun (e.g., Swimming is fun. I am good at cooking).

Passive Voice: The passive voice is used when the subject of the sentence is the recipient of the action. It is formed with "be" + past participle (e.g., The letter was written by John).

Passive Gerund: This combines both concepts. The formula is: $\mathrm{being}+\text{past participle}$ (e.g., He hates being ignored. She is afraid of being bitten by a dog).