Microsoft has steadily improved its operating cash flows in the past three years.
Microsoft has steadily improved its operating cash flows in the last three years.
Microsoft has steadily improved its operating cash flows for the past three years.
Microsoft has steadily improved its operating cash flows for the last three years.
Microsoft has steadily improved its operating cash flows
forthe past three years. ("for" omitted)Microsoft has steadily improved its operating cash flows
forthe last three years. ("for" omitted)Microsoft has steadily improved its operating cash flows during the past three years.
Microsoft has steadily improved its operating cash flows during the last three years.
Microsoft has steadily improved its operating cash flows over the past three years.
Microsoft has steadily improved its operating cash flows over the last three years.
Which of them are idiomatic and preferred? Are they interchangeable?
Best Answer
Each of the examples above is grammatically correct, but with a slightly different meaning.
First, the question of "past" or "last" is less important, and it may depend on context. To me, "past" means specifically that each of the three years in question has already ended, whereas "last" might include the current year. Context is more important than the choice of words here.
The phrasing is more important. This is somewhat subjective, but to me the different prepositions indicate these connotations: