 Re: The usage of the word 'about'
You don't need both "about" and the present participle verb in (a) : Letter to a friend describing a special occasion is fine. The participle has the same meaning as a relative clause - so the sentence means Letter to a friend which describes a special occasion. Alternatively you could say Letter to a friend about a special occasion.
About is necessary in all the other sentences, where you just have a noun phrase.
In some contexts you would also need to say A letter to a friend ... It's fine in a list like this, but in a sentence the article is necessary : Yesterday I wrote a letter to a friend about....
(e) could also be improved - the expression is "veterinary surgeon" rather than "veterinary doctor" but it's more usual to abbreviate it to vet. I'd phrase this as : A letter to a friend about working as a vet.
(Here about is necessary, because despite being in the -ing form, the verb is not a participle but a gerund - it's the nominalisation of the verb. It couldn't be replaced by a relative clause). |