On paper, the difference is structural. In speech, the difference is sonic. The first sentence carries a specific stress pattern (usually heavy stress on "John") that signals to the listener, "Do not blame anyone else."
After dictation, listen to the audio again without writing. This time, try to explain why the speaker used that tense. For example, hear "The committee are arguing..." (collective noun as plural) and recall the written rule. advanced grammar in use audio
Advanced Grammar in Use is a masterpiece of reference. But grammar lives in the air, not on the page. The is the bridge between passive knowledge and active mastery. It corrects your ear, accelerates your processing speed, and gives you the confidence to produce complex sentences under pressure. On paper, the difference is structural