How far is it from this town to London?
1. It is ten miles to London.
2. It is ten miles away to London.
3. It is ten miles away.
4. It is ten miles from this town to London.
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[Explanation]
1. It doesn't refer to 'this town' in #1. It is an impersonal pronoun. In #1, it refers to the distance.
2. In #2, it also refers to 'the distance.' Does 'it' refer to 'this town'?
3. In #3, it refers to 'the distance.' It doesn't refer to 'this town' or 'London.'
4. Definitely 'it' is an impersonal pronoun. 'It' refers to 'the distance' here.
(What do you think of my explanation? Would you correct some?)
Your explanation is mostly correct! However, there are a couple of minor adjustments I would make:
1. In sentence #1, "It is ten miles to London," 'it' does refer to the distance, but it is not explicitly stated that the distance is from 'this town' to London. So, it could be interpreted as a general statement about the distance to London from anywhere.
2. In sentence #2, "It is ten miles away to London," the word 'to' is unnecessary. The correct phrasing would be "It is ten miles away from London." Again, it doesn't specify that it is the distance from 'this town' to London.
4. In sentence #4, "It is ten miles from this town to London," you are correct that 'it' refers to the distance. Additionally, it specifies that the distance is from 'this town' to London, making it the most accurate statement.
Overall, your explanation is clear and concise!