In the negative-potential form, 切（き）れない will attach to the 連用形（れんようけい） form of other verbs, to express that a particular action is ‘unable to be completed’. Let’s look at some examples.
Are you going to order the large one? I don't think you can possibly finish the portion they serve here.
You can't possibly finish climbing this mountain in one day.
, which usually attaches to verbs to show that something was done to the point of running out, 切（き）れない
often implies the exact opposite. This means that the (A) verb cannot be completed specifically because there is too much/many of something in order to finish it.
There are too many stars in space to count.
This meat is so thick that it is not possible to chew with your teeth.
may also imply that something cannot be done ‘to the point of satisfaction’. In this case, the feeling of dissatisfaction is what the speaker considers too much to overcome.
I cannot possibly explain this feeling of mine with words. (Cannot explain satisfactorily)
I am so excited that I can't wait. (Cannot wait satisfactorily)