When visiting London, ...

[sitifan]

When visiting London, a lot people will use the Underground map as a guide for where to go and how to get there. (Kangxuan, Book 6, page 91)
Which is the correct paraphrase of the words in bold, "When they are visiting London" or "When they visit London"?

 

[Tdol]

I think you could use either of them.

 

[sitifan]

I think you could use either of them.

What's the difference in meaning between them?

 

[Rover_KE]

Effectively – none.

 

[sitifan]

Peter is afraid of the dark. He even leaves the lights on when sleeping. (the CAP exam, 2022)
Which is the correct paraphrase of the words in bold, "when he sleeps" or "when he's sleeping"?
In modern English, the second one.
The first one is dated.

He even leaves the lights on when sleeping.

Peter is afraid of the dark. He even leaves the lights on when sleeping. (the CAP exam, 2022) Which is the correct paraphrase of the words in bold, "when he sleeps" or "when he's sleeping"?

forum.wordreference.com

Why is it that "when he sleeps" is dated, but "when they visit London" is not dated?

 

[jutfrank]

The person who made that comment is mistaken. This is nothing to do with modern English.

Also, there is no 'correct' paraphrase. Both when he sleeps and when he's sleeping are natural and grammatical.