I have the following construction,

A context variable refers to a subset of the DOM tree nodes which represent a context.

I doubt if I should say

A context variable refers to a subset of the DOM tree nodes representing a context.

Or for

....another anchor which shares the same ancestor

...another anchor sharing the same ancestor

Are they both correct? In fact I don't know when to use ing in relative clause.

The examples of this source are in present continues form but examples of this one include present form too.

Can I always use the reduced relative clause with "ing" in present or present continues cases? or it is just for present continues? or for special cases of present? I got confused!

  • Actually you don't have present progressive (i.e. continuous) in any of these sentences. The first one is a reduced relative clause, it uses a non-finite -ing form (a present participle). Present progressive has to contain the verb to be (adequately inflected) so that wouldn't be a non-finite verb form any more.
    – Lucky
    Jun 14, 2015 at 18:17
  • @Lucky There is no first or second sentence, they are both one sentence. you mean the first option is correct and a reduced relative clause for the second option?
    – Ahmad
    Jun 14, 2015 at 18:37
  • Well the first option is a sentence and the second one is also a sentence, they are just very similar and mean the same thing :-). Both of those are correct and the first one contains a reduced relative clause: "representing a context". The way both relative clauses are written they refer to tree nodes not a context variable.
    – Lucky
    Jun 14, 2015 at 19:35
  • My poor grammar says that you need a comma before your which - 'nodes, which represent a context.' Or to use 'that' in place of 'which', but honestly, they both read very well as-is. Jun 15, 2015 at 17:30

1 Answer 1


It is always possible to replace a defining relative clause by a participle construction which is shorter. Longman English Grammar 1.58.6 (present participle) and 1.62.3 (past participle).


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