present perfect simple or continuous

[Liza]

Hi,

I've learnt about the present perfect tenses that if I want to say a quantity, I mustn't use the continuous form. e.g. She's written ten books (not she has been writing ten books).

BUT: Why do I meet this kind of sentences like?:

It has been snowing a lot.

Or maybe this sentence is not correct? but it sounds lOK. Or 'a lot' is not a real quantity? IBut think, it is. Or, maybe, it's an exception? So what is the final rule.

If I follow the original explanation, I should say I think: It has snowed a lot.

Am I wrong?

Thanks for your help.
Liza

[Alan]

Hi Liza,

I wouldn't worry too much about the firm use of certain tenses. It's more practical to concentrate on the meaning. If I say: I have been waiting for 30 minutes for the bus to arrive - it suggests I am going to continue waiting even longer. If I say: I have waited for 30 minutes for the bus to arrive - it suggests I have waited that long so far but there is no indication that I am going to wait any longer. There is a hint in that last sentence of completion at least until now. In your sentence:she has been writing ten books this use of the continuous suggests that she has never completed those ten books and that wouldn't make sense. You might like to look at something I have written for this site on the use of continuous forms:

Grammar Lesson: Progressive Forms

Alan
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English as a Second Language
You can read my ESL story Relative Pronoun