I am working with some students on Cambridge First and in the second part of the "use of English" there is an exercise in Part 4 you have to complete the second sentence so that it has a similar meaning to the first sentence, using the word given. You must use between two to five words.

The example is

All the trees apart from that big apple tree were blown over in the storm.

I have to use the word ONLY to fill :

That big apple tree was the ......be blown over in the storm.

My question is how do I explain the use of "was the only one not to be blown over"?

I know it is like that because it's like that, but how could I explain the conversion?

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    Very good question. I'll give you an answer tomorrow. In the meantime, you may wish to have a look here for the way that they are typically approached in EFL. Jan 28, 2016 at 22:18
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    It's a somewhat curious usage. A simpler example: He was the only one to be killed (the negation isn't important), which isn't usually quite the same as He was the only one killed. Personally, I'm a little uneasy about (I was) the only one to be wearing (fancy dress), because I think including to be works better when the "subject" is obviously being subjected to something (bad). It's too complicated for me as well right now, but excellent question, and I look forward to seeing how the answers go. Jan 28, 2016 at 22:29
  • @FumbleFingers Ok FF, I've done you an answer. Won't have time to proofread it till tomorrow though. Got to take my students to the pub for the social programme. Tough life being a language teacher ;) Jan 29, 2016 at 15:38

1 Answer 1


Infinitival relative clauses

We can make a special type of defining (read 'restrictive') relative clause in English using an infinitival clause. As with other relative clauses the infinitival clause comes after the noun it modifies. If we want to include the subject of the relative clause, we need to use for at the beginning of the clause:

  • They are the team [to beat].
  • They are the team [for us to beat].

In the first sentence we need to understand the Subject of the verb beat from the context. We probably understand it as people. In the second sentence the speaker has told us who the Subject is .

These types of relative clause usually have modal meanings to do with obligation of ability. They often mean something similar to should or can. We can understand the sentence above as:

  • They are the team [who we should beat].

Notice that just like other relative clauses these relative clauses have an antecedent. In our examples, the antecedent for the infinitival relative clauses is the word team. And like other relative clauses, these relative clauses also have a gap in them. We can model those sentences like this:

  • They are the team [(for people) to beat ____ ].
  • They are the team [for us to beat ____].

We use the antecedents to interpret the meaning of those gaps we understand the sentences like this:

  • They are the team [for us to beat this team]

or like this:

  • They are the team(i) [ for us to beat ____(i) ]

If the antecedent (strictly speaking, the gap) is the Subject of the relative clause, we cannot use for. We only use for when we use an overt Subject. If we don't us an actual phrase to say who the subject is, we don't use for. Here is an example:

  • She is the woman [the woman to lead us to victory]

Here we understand that the Subject of the relative clause is the woman. We have to have a gap in the clause where the subject is. We cannot use for:

  • She is the woman to lead us to victory.
  • *She is the woman for to lead us to victory. (ungrammatical)

In this example, we understand that the relative clause means something like who can lead us to victory.

Infinitival relative clauses with non-modal meanings

In special circumstances, we can use infinitival relative clauses with non-modal meanings. These are the special circumstances:

  1. The larger noun phrase must have a special modifier. It can be either a superlative like largest, youngest, most interesting, a special word like only, next, last, latest, or an ordinal number, for example first, second, hundredth.

    • Maria was the oldest runner to compete in the marathon.
    • Bob will be the only elephant to compete in the marathon.
    • Sherpa Tenzing Norgay was the first person to climb mount Everest.
  2. The antecedent must be interpreted as the Subject of the infinitival relative clause. All of these relative clauses have gaps as Subjects. From this we understand that in the first example above it was Maria who competed in the marathon. It was Bob who finished the race. The understood subject of to climb is Sherpa Tenzing Norgay.

Notice that because there is no overt Subject in the clause, just a gap, we cannot use for here.

Infinitival clauses have no tense. In these situations we understand the time reference of the infinitival clause from the context. We understand from the first, Maria, example that she was the oldest runner who competed in the marathon. WE understand from the elephant example, that Bob will be the first elephant who will compete in the marathon. We understand this from the verbs in the matrix clause.

Remember that to negate an infinitival clause we usually put not before the word to. Here are some examples:

  • You're the first person not to laugh at that joke.
  • It was the only tree not to be blown over.

Advice on teaching infinitival relative clauses

For FCE (Upper intermediate or B2 on the CEFR) you probably most need to teach the non-modal relative clauses. I wouldn't normally introduce them as relative clauses at all.

Students need to recognise modifiers such as first, only, next and so forth. They need to understand how to use infinitival clause like defining relative clauses to show which first, only or next thing we are talking about:

  • Maria was the first woman.
  • The first woman? What?
  • The first woman [to finish the marathon]

  • Bob was the only elephant.

  • The only elephant? etc etc

They need to understand how to negate such clauses, in other words the best place to put not.

The rest should fall into place. The terminology is not important. Nobody will ever test them on it. Good luck!


Don't try to teach these as a reduced form of wh- relative clause. Most infinitival relative clauses will not allow a wh- word at all. We can only use them in very, very special circumstances which are very difficult to identify and explain. Very often there is no easy transformation from a finite wh- relative clause to an infinitival one. The biggest danger however is that your students may try to transform relative clauses which don't meet criteria (1) or (2) into infinitival relative clauses. It simpler and easier just for them to understand if you just demonstrate how to use infinitival clauses in the same way that we use normal relative clauses - to define what 'only' or 'first' thing we are talking about.

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    Are you sure infinitival relative clause is relevant to OP's example? Or my simplified version? In most contexts He was the only one [to be] killed simply means nobody else except him was killed. I think your examples relate to what would be a somewhat contrived context for my example. (Perhaps several missionaries have been captured by cannibals, who single one out and say He is the only one [destined/required] to be killed for tonight's feast, while they're dragging him to the cooking pot.) The difference being that in yours, to [be] is required, not "optional". Jan 29, 2016 at 15:58
  • @FumbleFingers The OP's is an infinitival relative clause. Yours would be a partciple functioning as a post-modifier in a noun phrase. Prof Lawler would say that yours is an example of whiz-deletion (in other words a kind of reduction of a relative clause where the wh- word and the verb BE have been deleted). He would say the original before the deletion would be "I was the only one [who was] wearing fancy dress". As you said, yours is very unlikely to start out as "I was the only one to be wearing fancy dress". Also notice that yours ... Jan 29, 2016 at 16:04
  • @FumbleFingers ... doesn't need an only to be felicitous. For example you can just say "He was the man wearing fancy dress", but "This was the tree not to be blown over" is a bit weird, and we don't see infintival relative clauses like that. Also yours doesn't really have a gap in it - and so arguably is not a relative clause at all - unless you believe in whizz deletion! I'll read any more comments later - got to fly! Jan 29, 2016 at 16:07
  • There's nothing wrong with This was the tree not blown over. And so far as I can see both OP's and my examples actually do involve whiz-deletion (It was the only one which was blown over, He was the only one who was killed). I still think there's something curious about slipping to be into such constructions. I'm okay with He was the only one to be refused entry to the pub, but I'm a lot less sure about ...because he was the only one to be less than 18 years old. I think I'm gonna raise this on ELU. Jan 29, 2016 at 16:22
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    Well, I've just posted Restrictions on including TO BE in “the only one [to be] X” over on ELU, so let's see what comes of it. Note - it's critical that OP's cited example happens to require the word be as well as only. They could have left that out, in which case It was the only one blown over would have been perfectly okay. Jan 29, 2016 at 16:50

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