Hi Gencebay
Sentence No. 1 has a realtive clause and if it were shortened - or as I prefer to say, if a clause equivalent were used - it would read:
They spend a lot of time in their garden running right down to a river.That would be grammatically correct but it would mean that these people (= they) run to a river because there is a
preposition in the phrase
in their garden. That means it cannot be the subject of the clause equivalent
running right down to a river. Clearly, that is not what is intended. I don't know a grammatical reason that makes a clause equivalent impossible for sentence No. 2. There isn't a rule for everything, or if there is one for this, I don't know it. If we change the sentence a little, a clause equivalent is possible:
Harry, running alongside David, is his cousin.This seems to be against the rule in your grammar book. I have never heard that rule, by the way. Your mother tongue may be a more logical one than English, with fewer exceptions. It is impossible to have rules that cover
all usage of a language, especially the English language. You'll just have to learn English piecemeal and accept the oddities, there is no other way.
Bear in mind that you are learning a language whose speakers used a monetary system in which a pound was equal to 20 shillings and a shilling was equal to 12 pence. The same nation has built underground lines with curved tracks where station platforms are, creating gaps big enough for a child to fall down in them and necessitating announcements: Mind the gap!
And if you take a Piccadilly line tube to Heathrow Airport, you'll notice that the train floor isn't always flush with the station platform. It's sometimes two inches above it, sometimes two inches below.
![Smile [:)]](/emoticons/emotion-1.gif)
As far as the English language is concerned, expect the unexpected.
Cheers
CB