A private student of mine had to complete a gap fill text, which contained the following excerpt:
Pronunciation isn't my strongest point, therefore I've decided to improve it. I've borrowed some Spanish DVDs from the library, with the purpose of listening to native speakers and trying to copy them.
The correct answers, according to Cambridge English Complete CAE, were so and intention. Although I would have written so because a comma preceded the gap, and explained this to the Italian student (who rightly huffed) I could not explain why the noun, intention, was preferred. To me with the purpose of and with the intention of are synonymous.
If the phrase had been written as follows:
I've borrowed some Spanish DVDs from the library for the purpose of listening to native speakers and trying to copy them.
Would purpose have been more appropriate here? Should there be a comma after library? I ask because in the text above there is a comma preceding with (I loathe having to explain punctuation, but seeing as it's towards exam preparation I'd like to be as thorough as possible).
P.S. The exercise was not a multiple choice one, the learner has to supply the one word answer that best fits.
EDIT There is indeed an "and" in the last sentence, which I missed when writing the excerpt. Many thanks to Edwin Ashworth and @DavidSchwartz for pointing out the (mea culpa) transcription error.