Used to describe something that is possible in the future, though not guaranteed.
“The dog could knock over the vase if it keeps jumping on the couch.”
“If the driver doesn't slow down, the car could skid on the wet road.”
'Could' is useful in Task 4 for suggesting an alternative outcome, especially when the picture shows an ambiguous or risky situation. Using it alongside 'will probably' lets you present a main prediction plus a backup possibility, which examiners notice as strong, flexible language use. For example: 'The ladder looks unstable, so he could fall if he leans too far.'
Synonyms: might, may possibly, it's possible that