00 / Verbs & Tenses
Verbs of the senses
Verbs of the senses describe physical perception and take different complement structures depending on whether an action is completed or in progress.
B2Upper Intermediate
01 / Overview
Verbs such as see, hear, feel, watch, and notice are followed by an object and either a bare infinitive or a present participle. The choice between these two forms changes the aspect of the perceived action.
02 / Infinitive vs. Participle
The bare infinitive suggests you witnessed the entire event. The -ing form emphasizes the duration or that the action was already happening when you perceived it.
| Structure | Meaning | Example |
|---|---|---|
| Verb + Object + Infinitive | The complete action from start to finish. | I saw them cross the road. |
| Verb + Object + -ing | An action in progress or a part of an action. | I saw them crossing the road. |
03 / Passive Voice Construction
Subject + be + past participle + to-infinitive / -ing
When these structures are used in the passive voice, the bare infinitive changes to a to-infinitive. The -ing form remains unchanged.
04 / Common mistakes
I heard him to sing a song.
I heard him sing a song.
In the active voice, do not use 'to' with the infinitive after verbs of the senses.
She was seen enter the building.
She was seen to enter the building.
In the passive voice, the full infinitive with 'to' is required.
05 / Practice
I watched the plane ______ (land) until it finally came to a complete stop at the gate.
Show answer
Answer: land
Why: The context implies the speaker watched the entire process from start to finish, making the bare infinitive the most appropriate choice.
Walking past the kitchen, I smelled something ______ (burn).
Show answer
Answer: burning
Why: The present participle is used here because the speaker caught the action in progress while passing by.
The suspect was noticed ______ (climb) over the fence by a neighbor.
Show answer
Answer: climbing / to climb
Why: In the passive voice, we use either the -ing form for an action in progress or the to-infinitive for a completed action.