I think the more common recommendation (or appropriate) style is to use "if" in this sentence, "I wonder if I will ever see this again," because there is only one "option."

Alternatively, I would write "I wonder whether or not I will ever see this again."

The question came up when a native English speaker corrected one of my sentences. I'd be happy to hear your opinion on this.

  • Also related: "whether" vs. "if" – Nathaniel is protesting Sep 28 '15 at 2:48
  • Thanks for the links. So, it sounds both "if" and "whether" are okay here, but people tend to prefer "whether" in formal writing (in case of noun phrases such as the one above) – user99042 Sep 28 '15 at 5:51
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    Yes, both are fine, and "whether" is fine with or without the "or not". – hobbs Sep 28 '15 at 6:05
  • Thanks again, just wanted to make sure that I understood correctly. I marked the question as "This question already has an answer here:" due the other questions linked above. – user99042 Sep 28 '15 at 6:56