Is the preposition "for" necessary in the following sentence? In reports coming across my desk, I am seeing it written both ways (that is, with and without the preposition).

He worked for a total of 14 years.

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Comments  (Page 3) 
Well, dropping ' for ' is to avoid the repetition of it in a sentence I believe. Or maybe what I've read was written in lousy English in my local papers. They omit the first ' for '.

How about

eg. I have been waiting you for hours.Emotion: smile Of course ..... for you for hours won't be wrong though. Maybe for convenience sake, they use only 1 ' for ' in the sentenceEmotion: smile
I think it depends on how or where are you going to use it.

For example in you sentence, u can deduct the for if you want to state a fact ( he worked a total of 14 years). You can also use the word "for" if you really wanted to show importance in the number of years he worked.
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@ whl626 ref your view that : "You can also say, " I am waiting someone for his opinion " "

I really dont think you CAN say that!

@ buggahEmotion: smile

I use "for" in the sort of phrases you have mentioned. It maybe OK, in some dialects, to miss it out. Personally I think it needs to be in there.
Maybe you could say I have been waiting for someone's opinion.
you could, indeed, say that maj!
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How about ' Wait your turn ' ? Or ' Wait for your turn ' ?

Or ' wait your turn ' = wait for your turn ( just simply omit the ' for ' ) ?
these days I asked around many native speakers about

eg. I am waiting someone for his opinion.

At first I was confident of its correctness because it is always used in my local newspapers. But it seems that none would agree on the omission of ' for ' after ' waiting '.

My conclusion is that the local newspapers editors are somewhat at the similar level of me. Emotion: stick out tongue