Was not because of/ but of?

Question

How do I say this properly, when I want to say that the result was not because of x but of y?

For example: The outcome was not because of x but (of) y?

Do I use of here?

Edwin Ashworth · Answer

'Because of' is a compound preposition {see OALD} and is never [AFAIK] split.

A river cuts through rock not because of its power but because of its
  persistence.

The whole preposition may sometimes be omitted:

*/??A river cuts through rock not because of its power but its persistence.

but re-ordering may be required:

A river cuts through rock because of its persistence, not [because of]
  its power.

Teacher Lee · Answer

Original:  The outcome was not because of x but (of) y?

I would say parallelism (parallel structures) would require you at least to keep the "of" for clarity.

Either of the below would clearly show the parallel application of "because":

...not because of x but of y
...not because of x but because of y

Without the "of", the application of the parallel application of "because" to y is not clear.

2 Answers