cut a finger
The Spanish phrase 'cortar(se) un dedo' translates to 'cut a finger' in English. This can refer to accidentally cutting your finger with a sharp object such as a knife. In Spanish, reflexive verbs (indicated by 'se' in parentheses) are used when the subject and the object of the sentence are the same. In this case, 'cortarse un dedo' would mean 'to cut one's own finger'. This phrase can be used in various contexts, generally pertaining to cooking or any other activity involving sharp tools.
If you're not careful when chopping carrots, you might cut a finger.
The phrase encourages caution during a potentially dangerous task and hints at potential consequences. Given the mood used, it has an advisory tone and can be seen as a warning.
When I was a kid, I cut a finger with a soda can.
The sentence is framed in the past tense, recounting an incident from the speaker's childhood. It potentially shows the dangers that seemingly innocent objects can pose.
I cannot play the piano because I cut a finger.
The sentence is an explanation to a potential question about why the speaker is unable to perform a certain activity. It sets a causal link between an incident and its implications on an individual’s activity.