Grammar – ‘It Is Impossible’ or ‘That Is Impossible’?

grammarpronouns

Tell me please if there is any difference between it and that in the following context.

Person 1: Last week I bench-pressed 150 kilos.

Person 2: It/that is not impossible because the week before you bench-pressed only 135 kilos.

As a non-native speaker I cannot see the difference between it and that, so please help me see it if there is any.

Best Answer

Consider the following conversation:

You know that guy named Dmytro?
--The weightlifter?
Yeah. He bench-pressed 1000 pounds yesterday.
-- That's impossible! It's not possible for a human being to lift so much weight.

That refers back to what has just been said, that is, to the other person's claim that Dmytro lifted 1000 pounds. In this conversational context, that = what you said a moment ago.

It refers forward to what is being said now by the skeptic; you can understand it like this:

{Something} is not possible! What is the thing that is not possible? The impossible something = "for a human being to lift so much weight".

In this conversational context, it = what I am about to say.