Idioms

Step 1: Understanding the idiom: "To haul someone over the coals" means to severely criticize or reprimand someone for a mistake or wrongdoing.

Step 2: Analyzing each option:

To walk on burning coals: Literal meaning --- not correct.
To move around coal mines: Literal interpretation --- not correct.
To rebuke someone very strongly: Correct meaning.
To overhaul the machines: Unrelated meaning.

Thus, the idiom "to haul over the coals" means to rebuke someone very strongly.

Step 1: Understanding the phrase: The idiom "a cog in the wheel" refers to someone who is a small but necessary part of a larger system or organization. It suggests that while the person is important to the functioning of the system, they are not particularly outstanding or unique.

Step 2: Analyzing each option:

He is an obstructionist: Incorrect, a cog helps the wheel move, not obstruct it
He is a very special person: Incorrect, a cog is important but not necessarily special.
He is the driving force: Incorrect, a cog is just one part, not the whole force.
He is as important as any other person: Correct interpretation.

Thus, the correct answer is He is as important as any other person.