Yesterday, I taught some 15 Rules on the Subject-Verb Agreement to my M1 class at Cambodian Mekong University. Thanks to my students who are attentive. As I was preparing for my American Literature class this morning, I began to notice in the comprehension question something I had not thought about it before. The question goes like this: "What does he really want"? Suddenly, it dawned on me. I had already known that grammatically speaking this was the correct usage but I wasn't satisfied. Why is the verb 'want' not in the singular form to agree with singular pronoun 'he'? This prompted me to do some reading and research. My quest was rather why is this, not how is this. Although I have not found any rule yet in the use of 'DOES", I found some common usage that allowed me to formulate the TIP I've listed below.
The basic rule of subject verb agreement as we already knew states that a singular subject takes a singular verb, while a plural subject takes a plural verb.
1. He eats. 'He' is singular and 'eats' is singular.
2. They eat. 'They is plural and 'eat' is plural.
3. The students are enjoying the show.
4. The audience is enjoying the show. 'Audience' is collective noun and therefore takes the singular verb 'is'.
EXCEPTION TO THE RULE
But there is always exception to any rule. Why can you not say "Does she has a boyfriend?" The pronoun 'She' is a singular and according to the rule it should take a singular verb. The correct one therefore is Does she 'have' a boyfriend? Why can you not say "I has a boyfriend"? "I" is singular, so it should use the singular verb 'has' instead of have. Yet, we say, 'I have a boyfriend'. Why can we not say, "Do you has a boyfriend"? But instead, we say, Do you have a boyfriend?
Even if "DOES", "I", and "YOU" are singular, they take plural verbs.
This is why we say, "What do you think about this rule?" We do not say what do you thinks?
This is why we say, "What DOES he think about this rule"? We do not say, what does he thinks........?
This is why we say, "I think the rule is easy to remember". We do not say, I thinks.....
Remember: Use plural verb with "Does", "You", and "I" even if these are singular subjects.
ANOTHER EXCEPTION TO THE RULE: Use singular verb with always singular nouns.
This is nothing profound. Do your personal research. There are tons of stuff on the web about grammar.