Lesson

Phrasal verbs 5 - on/off (2)

On and off particles part 2

≈ 15 min 8 block(s)

Text

Phrasal verbs 5 - on/off (2)

This lesson focuses on common phrasal verbs with the particles on and off. These small particles often change the meaning of the base verb. In professional contexts you will frequently see these verbs in instructions, IT contexts, meetings and reports.

  • Phrasal verbs combine a verb + particle (on/off).
  • The particle can reverse or change the verb's meaning (e.g., 'turn on' vs 'turn off').
  • Many are separable (you can put the object between verb and particle) — check each verb.

Table

Common on/off phrasal verbs

Phrasal verb Meaning Example
log on / log off Access or disconnect from a system or account Please log on to the VPN before opening the client files.
turn on / turn off Start or stop a device or function Turn on the projector for the presentation; turn it off afterward.
switch on / switch off Start or stop electrical equipment; often interchangeable with 'turn' Switch off your laptop during the flight.
go off Start making a noise (alarm) or stop being active (electricity) The fire alarm went off during the drill.

Tip

Key rule: Watch the particle

The particle (on / off) changes the action's direction: on often means start/access/activate, off often means stop/disconnect/deactivate.

  • Use 'log on' or 'log in' to access an account; use 'log off' or 'log out' to disconnect.
  • Use 'turn on' / 'switch on' to start a device; use 'turn off' / 'switch off' to stop it.
  • Some verbs change meaning entirely with different particles — learn each phrasal verb separately.

Check whether the phrasal verb is separable (object between verb and particle) or not.

Example

Examples in context

Please log on to the company VPN before accessing the client files.

Turn on the projector for the presentation and turn it off when you finish.

The fire alarm went off during the safety drill this morning.

Switch off your phone or put it on silent during the meeting.

Tip

Common mistakes to avoid

Learners often make predictable errors with phrasal verbs. Watch out for these universal pitfalls:

  • Using the wrong particle (e.g., 'turn on' vs 'turn off') — changes meaning completely.
  • Forgetting prepositions required by the phrasal verb (e.g., 'log on to' vs 'log on').
  • Incorrect word order with separable verbs (placing the object in the wrong position).
  • Confusing synonyms and using a single-word verb where a phrasal verb is required (e.g., 'activate' vs 'turn on' in informal instructions).

When in doubt, check a reliable dictionary for whether the phrasal verb is separable and what prepositions it requires.

Quiz

Choose the correct sentence:

Hint: Think about accessing an account or system.

Quiz

Complete: Please _____ to the remote server before starting the update.

Hint: Think about how to say 'access the server' in IT contexts.

Quiz

Which sentence correctly uses 'go off' to mean 'start making a loud noise'?

Hint: Consider which option describes an alarm or device starting to sound.

Key Points

GrammarPoint

log on

phrasal verb CEFR B1 //lɒɡ ɒn//

to access a computer system or account

You must log on to the network before opening the application.

GrammarPoint

log off

phrasal verb CEFR B1 //lɒɡ ɒf//

to disconnect from a computer system or account

Remember to log off when you finish working on shared terminals.

GrammarPoint

turn on

phrasal verb CEFR A2 //tɜːrn ɒn//

to start a machine or activate a function

Turn on the projector before the meeting starts.

GrammarPoint

turn off

phrasal verb CEFR A2 //tɜːrn ɒf//

to stop a machine or deactivate a function

Please turn off the lights when you leave the meeting room.

GrammarPoint

switch off

phrasal verb CEFR A2 //swɪtʃ ɒf//

to stop an electrical device from working; to deactivate

Switch off your laptop during the flight to comply with the rules.

GrammarPoint

go off

phrasal verb CEFR B1 //ɡəʊ ɒf//

to start making a noise (alarm) or to stop working (electricity)

The backup generator went off during the storm and restored power.

Vocabulary

projector

noun CEFR A2 //prəˈdʒektər//

a device that displays images or slides on a large screen

The conference room projector is connected to the docking station.