How to say "for a while … for a while, sometimes … sometimes" in English?

In English grammar, only one of the related words can appear. For example, although ............. can only be used at the beginning of a sentence or the beginning of the next sentence. Similarly, in English, a moment ... a moment, sometimes ... is expressed in just one word. I personally suggest that "sometimes" is used to mean "sometimes", that is, what you do sometimes and what you do in the future refer to things that are operated within a certain period of time, so you can use some time. I hope I can help you!