My classmate argues that
Studying British girls is smart
is grammatically correct because
[Eating] {apples} is [healthy]
is correct. They are using "Studying British girls is smart" to mean "British girls who study are smart".
My classmate argues that
Studying British girls is smart
is grammatically correct because
[Eating] {apples} is [healthy]
is correct. They are using "Studying British girls is smart" to mean "British girls who study are smart".
My classmate argues that "Studying British girls is smart" is grammatically correct because "[Eating] {apples} is [healthy]" is correct.
Yes, the two sentences have the same construction: Subject, verb, adjective. In both sentences the subject is a noun phrase consisting of a gerund (the true subject) and an object of that gerund. Both sentences are grammatically correct.
They are using "Studying British girls is smart" to mean "British girls who study are smart".
And here they are no longer correct. We can compare "Studying" to "Eating" and "British girls" to "apples." The sentence is saying that It is smart (as generality) to study British girls, that is, to look at British girls and catalogue their hair color and accent and education level and everything else one does when "studying" something. This may be seen better if we flip the two sentences around:
- Eating apples is healthy.
It is healthy to eat apples.- Studying British girls is smart.
It is smart to study British girls.
To make the sentence mean what your classmate thinks it should, we can change just one word:
Studying British girls are smart.
The rest of the words in the sentence are still spelled the same, but by changing the verb is to are we have completely changed the function of the other words in the sentence. Now the subject, "British girls," is modified by an adjective, the gerund "Studying." Now the sentence means "British girls who are studying are smart."
The person in question is confused by homomorphism in the English language. There is a possibility of ambigous reading even if coordination is done right. Such ambigous cases, e.g. garden-path sentences, may be considered stylistically bad if they weren't meant as a joke. In this case coordination is wrong, so his phrase got wrong meaning.
In the declarative sentence "[Eating] {apples} is [healthy]" the gerund phrase "eating apples" serves as subject.
The verb "is" is predicate here and can be used only with singular subject.It removes any doubt how coordination is happening here.
If that person wants to coordinate predicate with "girls" as a subject of declaration, he must use verb in its plural form,"are". In that case, girls will be the subject and "studying British" - a sequence of adjectives. In his/her version "Studying British girls" is phrase serving as subject, where girls are object.