Reduced Clauses and Participles on the TOEFL ITP: How to Choose -ing or -ed Fast
Reduced clauses and participles in TOEFL ITP Structure: how to choose -ing or -ed fast, plus the double verb trap and dangling modifiers, with a quiz.
Ever seen a TOEFL® sentence with a verb ending in -ing or -ed but no is/are, and wondered which word is the real verb? That is a participle, and it usually comes from a reduced clause (a shortened relative clause).
In TOEFL ITP Structure, participles are one of the biggest sources of traps. The options are often designed to give the sentence two main verbs with no connector, or to make you pick -ing when the meaning is passive. Here are the 5 things you need to master. (The slides are in Indonesian; the article explains everything in English.)
Pattern 1: Present Participle (-ing) = Active Meaning
When a relative clause is active (the noun before it does the action), you can shorten it: drop who/which/that and change the verb to verb-ing.
Formula: Noun + who/which + active verb → Noun + verb-ing
The students who attend the seminar will get a certificate. → The students attending the seminar will get a certificate.
It means “the students who attend the seminar”. The students are the doers.
❌ The students are attending the seminar will get a certificate.
This sentence is broken because it has two main verbs (are attending and will get) and nothing joining them.
Key: Noun + verb-ing with no to be = “who/which does …”. It describes the noun; it is not the main verb.
Pattern 2: Past Participle (-ed) = Passive Meaning
When a relative clause is passive (the noun before it receives the action), drop who/which/that and to be, keeping only the past participle.
Formula: Noun + which/who + be + past participle → Noun + past participle
The proposal which was submitted yesterday was approved. → The proposal submitted yesterday was approved.
The trap: submitted looks like a simple past verb, so you might think it is the main verb. The real main verb is was approved. Submitted here means “that was submitted” and describes the proposal.
Watch irregular verbs. The past participle must be the right form:
❌ The book wrote by her became a bestseller. ✅ The book written by her became a bestseller.
Key: Noun + past participle with no to be = “that was …ed”.
Pattern 3: The Double Verb Trap
A clause can have only one main verb. If the sentence already has one, a blank near the subject usually needs a participle, not a full verb.
The airplane ______ on the runway will take off in ten minutes. ❌ is taxiing (two main verbs: is taxiing and will take off) ❌ taxies (same problem) ✅ taxiing (describes the airplane) ✅ which is taxiing (a full relative clause also works)
Why it is tested: the option with to be sounds complete and “safe”. But once the sentence already has a main verb, adding to be breaks it.
Trick: Before choosing, find the main verb of the sentence. If there is one, the answer must be a participle or a clause with who/which/that.
Pattern 4: Participles at the Start (Dangling Modifiers)
When a sentence opens with a participle phrase, the subject right after the comma must be the logical doer of that action. If not, you get a dangling modifier.
Walking through the dark forest, ______. ❌ a strange sound was heard (a sound cannot walk through a forest) ✅ the travelers heard a strange sound (the travelers were walking)
The same applies to past participles at the start:
❌ Built in 1890, visitors still admire the bridge. ✅ Built in 1890, the bridge is still admired by visitors.
The bridge was built in 1890, so the bridge must come right after the comma.
Trick: Ask “Who does (or receives) the action in the opening phrase?” That answer must be the subject after the comma.
Pattern 5: A Reliable Way to Choose -ing or -ed
A popular shortcut says “if a preposition (by, in, on, at) follows the blank, choose -ed”. That shortcut does not work on its own. Plenty of active participles are followed by prepositions:
✅ The students living in the dormitory pay lower fees. ✅ People waiting at the station were tired.
A more accurate approach:
- A direct object follows the blank (a noun receiving the action) → choose verb-ing. The company ______ the new smartphone had huge profits. → producing
- By + agent follows → almost certainly the past participle. The smartphones ______ by the company were exported. → produced
- Another preposition (in, at, on) or nothing follows → decide by meaning: does the noun do the action or receive it? Books ______ in English → books are written → written. Students ______ in Bandung → students live → living.
For transitive verbs (verbs that need an object), check for the object: if there is one, it is active; if not, it is likely passive.
Summary
| Situation | Choose | Example |
|---|---|---|
| The noun does the action | verb-ing | students attending the seminar |
| The noun receives the action | past participle | the proposal submitted yesterday |
| The sentence already has a main verb | A participle, not be + verb | the airplane taxiing on the runway |
| Participle phrase at the start | Logical doer right after the comma | Walking …, the travelers heard … |
| An object follows / by follows | -ing / past participle | producing the phone / produced by the company |
Quick Quiz
Choose the correct option:
- The man ______ next to the window is my professor. (a) sits (b) sitting (c) is sitting
- The data ______ in the survey were incomplete. (a) collecting (b) collected (c) were collected
- Having finished the exam, ______. (a) the room was quiet (b) the students left the room (c) the bell rang
- The river ______ through the city is heavily polluted. (a) flowing (b) flowed (c) flows
Answers:
- (b) sitting, the man does the sitting, and the sentence already has the main verb is.
- (b) collected, the data were collected (passive).
- (b) the students are the ones who finished the exam.
- (a) flowing, the river flows (active; flow takes no object).
To get comfortable with past and past participle forms, read the 12 Tenses Guide and Parts of Speech 101.
Drill Participles Until They Click
Telling -ing from -ed in seconds takes practice. The more often you see these patterns in real questions, the faster you spot the main verb and the doer of the action.
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