Perception Verbs Quiz
10 multiple-choice questions on see/hear/watch/notice + object + bare infinitive or -ing, and the passive to-infinitive rule that catches out even advanced learners.
This quiz checks how confidently you can apply perception verb patterns at B2-C1 level, with questions built around real sentences like "I saw her cross the street" and "She was seen to cross the street" rather than abstract rule statements. Each question presents a full example, so you have to judge whether the action was witnessed complete or in progress, and how the passive voice changes the form. Read the full Perception Verbs grammar guide first if you need a refresher.
If a question catches you out, the FAQ section below explains the underlying rule in more detail, including the tricky passive to-infinitive exception. Reviewing the explanation immediately after an incorrect answer, then retrying the quiz on a different day, builds more durable grammar knowledge than repeating the same 10 questions back to back.
Perception Verbs — FAQ
What are perception verbs in English grammar?
Perception verbs describe what we perceive with our senses: see, hear, watch, notice, feel and smell, along with the phrasal verbs listen to and look at. They can be followed by an object plus a bare infinitive (e.g. "I saw her cross the street") or an object plus an -ing form (e.g. "I saw her crossing the street"), and the choice between the two changes the meaning.
What is the difference between "I saw her cross the street" and "I saw her crossing the street"?
"I saw her cross the street" means you saw the complete action from start to finish — the whole crossing. "I saw her crossing the street" means you saw her in the middle of the action, in progress, and you may not have seen the beginning or the end. The bare infinitive reports a complete event; the -ing form reports an action already underway or only partly witnessed.
How do you make the passive of "I saw her cross the street"?
In the passive voice, the bare infinitive after a perception verb changes to a to-infinitive: "She was seen to cross the street." This is an important exception to the usual "no to" rule for perception verbs, and it only applies to the bare-infinitive pattern, not the -ing pattern.
Does the -ing form change when you make a perception-verb sentence passive?
No. The -ing form stays exactly the same in the passive voice. "I saw her crossing the street" becomes "She was seen crossing the street" — no "to" is added, unlike with the bare infinitive, which does require "to" in the passive.
Is "I saw her to cross the street" correct?
No, this is incorrect. In the active voice, perception verbs like see, hear, watch and notice are followed by the bare infinitive with no "to": "I saw her cross the street." Adding "to" in the active voice is one of the most common mistakes learners make with this structure. "To" only appears once the sentence is made passive.
Which verbs follow this object + bare infinitive/-ing pattern?
The main perception verbs that follow this pattern are see, hear, watch, notice, feel and smell, as well as the phrasal verbs listen to and look at. All of them can take either an object + bare infinitive (for a complete action) or an object + -ing form (for an action in progress).
What is the difference between "I noticed her leave" and "I noticed that she seemed tired"?
"I noticed her leave" describes direct sensory perception — you physically watched her leave the room. "I noticed that she seemed tired" reports a mental observation or inference about her state, not a single physical action you watched happen from start to finish. The object + infinitive/-ing pattern is used for direct perception, while a that-clause typically reports an inferred observation.
Can the -ing form describe a repeated or habitual action?
Yes. Besides describing an action caught in progress, the -ing form after a perception verb can also suggest that the action was repeated, continuous or longer in duration, such as "I keep hearing him complaining about the traffic." The bare infinitive, by contrast, usually describes a single, complete, often shorter event witnessed in full.
Is this the same as causative verbs like make, have, let and get?
No. Causative verbs (make, have, let, get someone do something) describe causing or allowing someone else to perform an action. Perception verbs (see, hear, watch, notice, feel, smell) describe what you directly witnessed happening, using the same object + bare infinitive/-ing structure but for a completely different meaning. See our separate causative verbs guide for that pattern.
At what level is this perception-verb structure typically taught?
This structure, especially the meaning contrast between the bare infinitive and -ing and the passive to-infinitive exception, is typically introduced at B2 level and refined at C1, since it requires learners to already be comfortable with basic verb patterns, infinitives, gerunds and the passive voice before tackling the nuance between the two forms.