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?