Sentence improvement — Best preposition for temporal cause: choose the most concise alternative to ‘‘My friend was in hospital for a week after an accident’’ so the time-cause link reads naturally and formally.

Given data
Original: ‘‘My friend was in hospital for a week after an accident.’’

Concept/Approach
The preposition ‘‘following’’ is a concise, formal synonym of ‘‘after’’ when indicating time sequence due to an event: ‘‘… for a week following an accident.’’

Option analysis
through — Means ‘‘during/throughout’’; does not indicate the triggering event.following — Best fit; succinct temporal-causal connector.for — Duration marker; does not replace ‘‘after’’ properly in this slot.No improvement — ‘‘after’’ is acceptable, but ‘‘following’’ is more compact and idiomatic in reports.subsequent to — Overly formal/wordy compared with ‘‘following’’.

Verification/Alternative
Standard news style: ‘‘was hospitalized for a week following an accident.’’

Common pitfalls
Using prepositions that change meaning (‘‘through’’) or add unnecessary heaviness (‘‘subsequent to’’).

Final Answer
following