I had doubts on this so I asked this on Quora and Englishforums but to my surprise they gave conflicting answers. I want to know which of these sentences are grammatically correct in formal and informal Written & Spoken English. Even though these examples are quite a few, a few general points should encompass them all, I think.
- He is the patient and/(as well as) the doctor.
- He is both the patient and/(as well as) the doctor
- He is a patient and/(as well as) a doctor [too].
- He, the patient and/(as well as) the doctor, is a good guy.
- The patient and the doctor is a good man.
Now, I am quite sure that in all of these sentences, if we remove the second "the", the sentence would be grammatical but I want to know whether these sentences are grammatical at present. So, the most credible response I got was that all of these sentences are grammatically correct but the last one is 'odd' without some context. But he didn't say whether this is so for formal English too or just for informal English.
On the other hand, most of the others said that these sentences are not grammatically correct because the second "the" in each of these sentences makes the phrase plural -- i.e., as if 2 persons were being referred to there. I countered that they seem to be valid examples of parallelism, but they said they're not.
So, what is the truth here? I would really appreciate your help.
EDIT: I'm totally ignorant about this. I don't know what place to look at to gain some knowledge regarding this. It would really help me if someone cites a website article or book where I can read up on this.