Actually, I'm not sure any of them are flat our incorrect. I would say: 1. most common 2. next most common 3. kind of odd And actually, more common that any of those: Sometimes she is strict.

There is only one word in the sentence, "is", that the adverb "sometimes" can possibly modify. For that reason, it makes no difference whatsoever where you place it. If there were another word that "sometimes" could modify, then it would become important where you put it. Here's an example: "She is sometimes strict about how the children study." In that sentence, "sometimes" could modify "is" or "study" so if you put it in different place, the meaning would change: "She is strict about how the children study sometimes".

Adverbs of frequency (always, sometimes, never) typically come after the main verb: - I never go to parties. - I will never go to a party. - I have never gone to a party. However, if the main verb is To Be, the adverb of frequency will typically come after it. - I am always tired. - I am never bored. But, many adverbs of frequency can come at the end of a sentence, which is especially true of the AoF "sometimes" - I go to parties sometimes. - I am bored sometimes.

She is strict sometimes

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