Why is "a part of" - incorrect; "a large part" - correct?

[Queen09]

From the study material I am referring, the follwowing sent is incorrect because of article 'a'.

This strategy was a part of their corporate social responsibility.

Per the source, 'part' is used with an article only when there is an adjective e,g, a large part.

Can anyone confirm is there is such strict rule.

[Alan]

Hi'

It really depends on what you want to stress. You could say: Short term contracts are part of employment these days. You could also say: This is a part of the language that I find most difficult. In the first sentence you are talking generalities. In the second sentence you are referring to 'one' part.

Alan
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English as a Second Language
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[Cisco795]

Hi Alan good evening.

Do count and non count nouns has anything to do with the use of the indirect article (a)?

I noticed where there is a non count noun, there is no direct article either. (unemployment, responsibility), whereas as in "a part" (one of many) (count noun) you used the indirect article.

"A large part" defines a count noun, whereas "a part of" might define both, count and noncount.

Please correct me if I am wrong.

God bless.
Cisco.
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