Which one should I use who or whom?

Question

Which of the following sentences is correct?

This car should be used sparingly by whom is concerned with efficiency.

This car should be used sparingly by who is concerned with efficiency.

and why?

Answer 1

1. This car should be used sparingly by xxx [who is concerned with efficiency].
2. This car should be used sparingly by [wh--- is concerned with efficiency].

The Original Poster is attempting a grammatically sophisticated sentence. They are trying to use who a bit like the pronoun what. Consider the following sentences:

• You should do the activities [which make you happy].
• You should do [what makes you happy].

The first sentence has a relative clause which makes you happy. This clause is modifying the noun phrase the activities. Inside the relative clause, the word which refers to the activities. We say that the noun phrase the activities is the ANTECEDENT for the relative clause.

In the second sentence you will see that there is no antecedent. The word what means the thing(s) which. Notice that this whole relative construction is the object of the verb do. There is no noun phrase which the word is modifying. We call this kind of clause a fused relative.

Now, the word what can appear freely in fused relatives, but the wh- words who, which, when and where, cannot usually appear in fused relatives if they are the Subject of that clause. Even when they aren't Subjects, they only appear as the heads of fused relatives with a very few verbs such as choose, want and like.

• *You can have the party [where is convenient]. (not good)
• *I'll take [which she wants]. (not good)
• *[Who said that] is an idiot. (not good)
• *[Where she goes] she has problems. (not good)

The sentences above are not good because we are using these wh- words without an antecedent for the clause. In other words, we are using them in fused relative constructions.

If we want to use these relative words in fused relative constructions, we need to add the suffix -ever. This will give us a new relative word that we can use freely in fused relative constructions:

• You can have the party wherever is convenient.
• I'll take whichever she wants.
• Whoever said that is an idiot.
• Wherever she goes she has problems.

In the Original Poster's sentence there is no antecedent for who is concerned with efficiency. There are two ways to resolve this problem. Firstly we could put an antecedent into the sentence as in (1) at the top of this post. Here are a few suggestions:

• This car should be used sparingly by those [who are concerned with efficiency].
• This car should be used sparingly by drivers [who are concerned with efficiency].
• This car should be used sparingly by anyone [who is concerned with efficiency].

Alternatively, we could use a pronoun with -ever:

• This car should be used sparingly by [whoever is concerned with efficiency].

The problem with this sentence is that we like to use whoever when we are picking out a specific known group or are selecting people from a narrow set. Because we are identifying an almost unlimited group of people from an unbounded set the sentence doesn't work very well. If you were speaking to a small group of drivers, say ten people, the sentence above would be fine. It's not great however, for the Original Poster's requirements. For this reason I would choose the first or third examples above:

• This car should be used sparingly by anyone who is concerned with efficiency.

However, this relative clause begins with who is. We can make the sentence snappier if we delete the who is:

• This car should be used sparingly by anyone concerned with efficiency.
• This car should be used sparingly by those concerned with efficiency.

Here the relative clauses have turned into participle clauses modifying the words anyone and those.

Answer 2

The mnemonic I use for that is that when him will work, whom will too.

So swap in "him":

... him is concerned with efficiency.

Since "him" doesn't work here, neither does "whom".

... he is concerned with efficiency.

We have a winnah!

Answer 3

Neither...

I would reword:

This car should be used sparingly by anyone concerned with efficiency.