The sentence below (1) is from the Cambridge Online Dictionary:
(1) Early in the Autumn Term there is a reception at which you can meet current staff and students. (which refers to a reception and is the complement of at).
If there is a relative pronoun, I can easily separate the sentence into two parts so the above sentence is like:
a. Early in the Autumn Term there is a reception
b. at that reception, you can meet current staff and students.
The sentence below (2) is from The Economist
(2) There is something on which to build.
It is different from:
(3) There is something to build.
(3) means you are building "something", whereas (2) means you are building whatever on "something".
So with the same logic from the Cambridge Dictionary, 'which' refers to 'something' and is the complement of 'on', right?
But because the relative pronoun 'which' is used, I feel like there should be 'a clause' rather than a dangling phrase. And I can't really separate the sentence into two like I did before for (1).
Any sources you will find will tell you "Relative pronouns introduce relative clauses." But (2) really isn't a "clause", if you know what I mean.
(2) There is something on which to build.
How is it that "which" introduces a relative clause on the sentence above?