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When and where to use 'since' and 'for' in the sentences of present perfect continuous and past perfect continuous and future perfect continuous?
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AnonymousWhen and where to use 'since' and 'for' in the sentences of present perfect continuous and past perfect continuous and future perfect continuous?
Use 'since' with a point in time. Use 'for' with a period of time. Place these phrases at the end of your sentence.

I have been working in the garden since 9 o'clock this morning.
I have been working in the garden for three hours.

I had been living in Chicago since 1983.
I had been living in Chicago for 15 years.

After since you can have a full clause to indicate the point in time you are referring to.

I have been working in the garden since I finished eating lunch.
I had been living in Chicago since Mr. Daly was elected mayor of that city.

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With the future perfect continuous, an expression with since is not natural.

??? I will have been speaking English since 2005.< not natural
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And even with for, additional information is needed to complete the meaning, typically an expression that begins with by or by the time (that).

I will have been speaking English for six years by the time that I am 30 years old.
I will have been living in this house for 30 years by the time the mortgage is paid off.

CJ