These questions ask how an action was performed, who performed it, what tool was used, or which fixed means expression completes a sentence. The same object can be described differently depending on its role.
Classify the role and the noun frame
Ask a role question before looking at the preposition. Who did the action points to the agent frame; what physical tool was held points to the instrument frame; how someone travelled or paid points to a means frame. Then inspect the noun phrase. A bare transport noun works with by, but a particular vehicle with a determiner returns to the place system. For example, a parcel may be delivered by a courier, a seal may be opened with a small blade, and commuters may travel by tram but sit on the late tram.
| Signal | Choice | Original example |
|---|---|---|
| Doer in a passive clause | by | approved by a manager |
| Hand-held instrument | with | tighten it with a wrench |
| General travel means plus a bare vehicle noun | by | travel by ferry |
| Particular public transport with a determiner | on; use in for a car or taxi with a determiner | on the morning bus; in her taxi |
| Manual production, accidental event, unplanned event, deliberate act | by hand, by mistake, by chance, on purpose | assembled by hand; sent by mistake; chosen by chance; delayed on purpose |
| Language or visible writing medium | in | written in Italian; signed in ink |
| Codified payment method | by card, in cash | pay by card; pay in cash |
Medium and instrument are related but not identical. A note can be written in ink when the visible medium matters, or written with a fountain pen when the physical tool matters. The noun shape also matters in payment expressions: by card is a bare method frame, while with a card can describe the physical act.
Where similar meanings mislead
| Trap | How to reject it |
|---|---|
| With for a person who performs a passive action, or by for a hand-held tool | Separate agent from instrument. The doer follows by; the physical tool follows with. |
| By before a vehicle phrase containing the or another determiner | The bare-noun means frame is no longer available. Use the ordinary in or on location pattern for that vehicle class. |
| One preposition reused for every manner phrase | Memorise the complete units: unintended and unplanned events use by, while deliberate action uses on. |
| By before a language name | A language is not the doer of the writing. It identifies the linguistic form, so the frame uses in. |
| With plus a bare payment noun | The bare method expression is by card. If with is used for the physical act, it needs a determiner before the object. |
Try it
Which expressions correctly use a bare transport noun to state the means of travel? Select all that apply.
- by train
- on train
- by bus
- with the plane
A pencil was used. Name the writing medium, not the instrument, and complete the phrase: write the labels ….
Choose the codified payment-method phrase: At the counter, she paid … cash.
- by
- in
- with
- on