I was reading a grammar and saw this. ---------- Achievement verbs describe actions that occur instantaeously. - He solved the problem. - He spotted the airplane. These verbs fall into two classes - one is 'punctual', and the other 'change of state' (..cut..) - Change of state - find a solution, cross the finish line - This involves a preliminary activity that culminates in the act denoted by the verb. Thus, a person searches before finding the solution, and runs toward the finish line before crossing it. (..cut..) With change of state verbs, progressive aspect may or may not be possible, **depending on whether the activity leading up to the achievement is treated as being the same activity** For example, - 'His train is arriving at noon.' is acceptable - '* She is recognizing the thief.' is not acceptable. ---------- I feel that 'She is recognizing the thief.' is strange, but as I don't understand the bolded part, I can't get the reason. Would you help me with this?