In the book "Horizons: exploring the universe-Cengage learning (2018)", it said:

Only during totality, when the photosphere is completely hidden, is it safe to look at the Sun directly.

So I was wondering why the author wrote "is it safe ... directly." Is it correct in terms of grammar? Shouldn't it be "it is safe.. directly."?


1 Answer 1


The author wrote it that way because they had chosen to 'invert' the sentence to emphasise the phrase only during totality.

Normally, the sentence would read :

It is safe to look directly at the Sun only during totality.

...but when the only phrase is moved to the beginning, the convention is to change the order of the words in the main clause.

Only when I'm in the country do I feel really happy.

  • Well, your second sentence may not be a great example, because the uninverted version would drop the "do" entirely: "I feel really happy only when I'm in the country."
    – ColleenV
    Sep 14, 2021 at 17:24
  • @ColleenV - OK, granted. Sep 15, 2021 at 8:02

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