Reduced Relative Clauses

With an active -ing form, the noun being described must be someone or something that can perform the corresponding verb: colleagues work, a cable carries a signal. In the full clause, who/which/that occupies the subject position of the relative clause itself.

The noun may be the subject, object, or object of a preposition in the main sentence. Do not apply here the rule for initial adverbial phrases such as Walking home, I…: that involves a different syntactic relationship. If a separate subject performs the action in the full relative clause, mechanically replacing the clause with -ing will change the participant.

In the transparent pair who is working → working, remove the relative pronoun who together with the form of be. Do not leave who working or is working without who inside the modifier. For a simple active verb, correspondences such as which connects → connecting are possible if the meaning is naturally preserved.

-Ing does not agree with the number of the noun: the route connecting…, the routes connecting…. However, the main predicate agrees normally. The spellings travelling and traveling are both acceptable; they are not different grammatical constructions.

The name present participle does not make this form a present tense. We understand the time from the main sentence, adverbials, and the situation. The same form can describe participants in yesterday’s event or in a meeting already planned for tomorrow.

Not every -ing modifier describes an action in progress. Containing, resembling, and leading can name contents, resemblance, or a stable characteristic. A folder containing receipts naturally corresponds to a folder which contains receipts; it does not require the progressive form is containing.

To negate an -ing modifier, put not before its verb group: people not attending. This non-finite construction does not need do/does/did. Negating the main predicate means something different: people attending did not vote — the people attended, but they did not vote.

When reducing the clause, preserve the scope of negation. Applicants who do not meet the requirements → applicants not meeting the requirements does not mean applicants meeting the requirements. Do not add a cause or consequence if none was present in the conditions.

The possibility of forming an -ing expression does not guarantee an equivalent sentence. Can, must, and might express ability, obligation, or uncertainty. If they are simply removed, the description may turn into a statement about an action or property. Keep the full relative clause when the modal meaning is important.

Likewise, do not erase the difference between an action completed earlier and an activity at a particular time. Who had already submitted cannot be thoughtlessly replaced with submitting. When necessary, keep the full form with its tense and aspect. This lesson does not teach a universal procedure of “delete the words and finish the rest with -ing.”

Without commas, the modifier can identify the required subgroup: researchers working abroad — specifically, the researchers who work abroad. Commas present the description as additional information about an already identified group or person. Do not add or remove commas automatically when reducing the clause.

Place an -ing modifier close to the noun it refers to. Long strings of descriptions make reading more difficult; a full sentence is sometimes clearer. The short form is common in writing, but natural short descriptions are also familiar in speech.

First, identify the noun you are describing and mentally restore the full modifier. Then check the verb form, the time in the context, negation, and important modal meanings. Finally, make sure the main predicate remains in place and that the sentence reports the same facts.

In exercises requiring -ing, the full relative clause may not meet the learning objective, but it is not therefore ungrammatical. In open-ended answers, the models show possible solutions: other natural words and word order are acceptable if the stated content and grammatical conditions are met.

For regular verbs, the past participle often ends in -ed: checked, delivered, repaired. Irregular verbs require a separate form: write — written, take — taken, draw — drawn, build — built. The past-tense form wrote cannot replace written in a passive modifier.

Compare roles, not just spellings: people interviewing candidates conduct the interviews; people interviewed by the panel undergo them. A person can have a passive role, and a thing can be the subject of an active verb. A rule such as people = -ing and things = past participle therefore fails.

The past participle does not change with the modified noun’s number. However, the main verb agrees with the head of its subject phrase: the invoice ... is, the invoices ... are. A noun after by does not control that agreement.

Find the noun modified by the participial phrase. That noun is the understood subject of the corresponding full passive relative clause. It is not necessarily the main-clause subject: in We checked the parcel delivered at noon, the main subject is we, but the delivered item is the parcel.

Place the modifier close to the intended noun. If other noun phrases accumulate between them, readers may not know what was checked, printed or repaired. Reword the sentence or retain a full relative clause instead of relying on guesswork.

If the original clause is active, simply deleting that is insufficient. Check the roles first: the parcels that the courier delivered corresponds to the parcels delivered by the courier. The courier becomes a by-phrase; the parcels remain what was delivered.

The term past participle names a form, not a compulsory past-time meaning in every sentence. Context determines the timing and character of the event: goods delivered every morning refers to regular delivery; goods delivered yesterday refers to yesterday’s event. The participle alone does not say that the activity has stopped or its result no longer holds.

An ongoing process can be expressed through the passive construction being + past participle: the roof being repaired. This explicitly retains the progressive perspective of which is being repaired. The -ing ending belongs to auxiliary being; the main verb remains a past participle.

A simple past participle can sometimes also receive an ongoing or future interpretation in sufficient context. Do not turn repaired versus being repaired into an absolute completed-versus-uncompleted test. If progress matters to the message, being repaired or a full clause makes it explicit. If precise time perspective or a complex relationship between events matters, the full form is often clearer.

Shortening a clause does not authorize changing the facts. In not approved by the editor, not negates approval and by the editor identifies the agent. If those details distinguish the intended items or matter to the message, retain them.

Do not mechanically reduce clauses with may, must, should or other modal verbs to a bare past participle. Devices that may be replaced expresses possible replacement; devices replaced does not express that possibility explicitly. Both phrases can be grammatical, but they are not automatically equivalent.

Similarly, check frequency, dates, earlier time reference and restrictions with only. Do not invent an unstated agent. A by-phrase can be omitted when it is unnecessary for the message, but should not be removed from an exercise or real communication where authorship or responsibility is the point.

A modifier without commas often identifies exactly which things are meant: the boxes opened by customs means those boxes that customs opened. It does not claim that customs opened every box in the world, or even every box in this delivery.

If the items are already unambiguously identified, a passive phrase may add supplementary information. In writing, set it off with commas; in the middle of a sentence, both commas are needed. This concerns the organization of meaning, not a change in the participle’s form.

Omitting commas does not always create an ungrammatical sentence; often it changes the reading. Check whether you need to select a subgroup or add information about items already identified. Do not mechanically insert commas around every past participle.

First state the main action: what should be read, sent, collected or discussed. Then identify the relevant noun through an action performed on it. The concise construction should help the recipient find the right item, rather than simply make the sentence longer.

Before sending, check three things: the modifier’s noun is clear, the passive role and participle form are correct, and no important information has disappeared. If a full clause is needed to preserve modality or time perspective, keep it. Concision should serve meaning.

This lesson practises passive modifiers after nouns, not every participial construction. Initial adverbial phrases such as Encouraged by the feedback, ... relate to the sentence differently. Ordinary adjectives and active -ing forms appear here only as necessary contrasts.

In a simple active construction, the person or thing being described performs the infinitive action: in the researcher to identify the fault, the researcher identifies it. Use the base form after to, without -s, a past ending or -ing.

The full form who identified can become to identify when the context supports this modifier. Do not retain who before an ordinary to identify. The main verb of the sentence remains: She was the first researcher to identify the fault.

To arrive does not automatically mean the future. In an account of yesterday, it can correspond to who arrived; in a schedule with next, it can describe someone still to arrive. The main verb and context establish the time.

To have + V3 explicitly marks earlier experience or completion before a reference point. However, not every past fact requires a perfect infinitive: She was the first to arrive yesterday is entirely natural.

If someone performs the action, use to interview; if someone interviews them, use to be interviewed. Form the passive infinitive with to be + V3. When necessary, combine prior completion and the passive: to have been interviewed.

Do not arbitrarily remove the subject inside an object relative clause. In the first candidate that the panel interviewed, the candidate is the object of interview. The first candidate to interview the panel reverses the roles. To preserve the event, recast it in the passive: the first candidate to be interviewed by the panel.

First, last and next indicate a place in a sequence; only singles out one participant with a particular property. The only candidate to pass does not mean that there was only one candidate altogether: the others may have failed.

Negation applies to the action it precedes. The only person not to reply means that one person failed to reply, not that only one replied. Not to is a useful neutral order; to not is also possible and should not be declared ungrammatical.

A full relative clause remains correct: the first person who arrived. If an exercise requests an infinitive, this answer does not meet the particular learning objective, but it is not grammatically incorrect.

The only candidate waiting outside is also grammatical: it describes someone currently waiting outside. The only candidate to pass describes a result. Only itself does not prohibit -ing; the meaning relationship matters. Do not turn every relative clause into an infinitive: the colleague who lives upstairs does not automatically mean the colleague to live upstairs.

Modality cannot simply be deleted either: the only colleague who might know the answer expresses uncertainty. The only colleague to know the answer presents the knowledge as a fact. If the concise version loses a necessary nuance, retain the full clause.

First identify whom or what you are describing, which property you are comparing and whether the event has already happened. Then check who performs the action and whether a passive is needed. Only then choose a concise infinitive construction.

Do not force an infinitive into every sentence of your own writing. One expression such as the first team to… can convey the key fact, while the following sentence explains its cause or consequence. Personal facts are unnecessary: you can describe an imaginary situation.