In only when , there is a sense of urgency, a slightly more 'involved' writing.It was only when is by comparision more 'relaxed' writing, more like someone is recounting something to someone.Which is grammatically correct?I can only do so much in this time.Or i can do only so much in this time.The question asks for a general answer but gives only one special context.In general, only and but only are not substitutable.
Free Images : blue, bubble, freshness, glass bottle, mineral water
Free Images : blue, bubble, freshness, glass bottle, mineral water

Free Images : blue, bubble, freshness, glass bottle, mineral water of I Only Drank Soft Sparkling Water For A Month. Here’s What Happened. .

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*they but only work that way occasionally.