down-phrasals — match the verb to its causer (GiU Unit 142)
The frame
Section titled “The frame”The storm caused a lot of damage. Many trees were blown down. ✓
The sentence names the agent (the storm). The down-verb must match its natural causer.
Causer → verb
Section titled “Causer → verb”| down-verb | needs this agent | example |
|---|---|---|
| blow down | wind / storm | trees were blown down in the gale |
| burn down | fire | the house burnt down |
| cut down | tool / people with saws | they cut down the old oak |
| cut down on | reduce intake/amount (needs the on) | cut down on sugar/gaming/spending |
| knock down | vehicle / demolition | he was knocked down by a car · they knocked down the wall |
| fall down | nothing — intransitive, no passive | the shed fell down (✗ was fallen down) |
| break down | machine fails / lose control (emotion) | the car broke down |
| close down | business/stops trading | the shop closed down |
| slow down | reduce speed | slow down before the corner |
Why not burnt / knocked here
Section titled “Why not burnt / knocked here”- burnt down — storms don’t burn; needs a fire in the sentence
- knocked down — needs a vehicle or demolition crew; a storm blows rather than hits
- cut down — needs saws/people
- fall down — can’t be passive at all
Rule: find the causer in the sentence, then pick the down-verb it can drive. Wind→blow · fire→burn · tool→cut · vehicle→knock · nothing→fall.
Form note
Section titled “Form note”Passive uses the past participle: were blown down (✗ blew down), was burnt down, was knocked down. Same irregular set as blow/blew/blown, throw/thrown, grow/grown.
Source
Section titled “Source”Raymond Murphy, English Grammar in Use, Unit 142 — Phrasal verbs up/down. Ebot lesson 2026-09-05.