Translation of aufjagen

He also told me that he had build his scooter by himself. I could not understand how a doctor was able to build such a machine on his own. It seems that the circumstances made people capable of many things.
Certainly, in a healthy mind, these feelings should not arise from bad thoughts. Not only the thought but also the reaction which arises and develops from this thinking is racism. Do you understand?
Is there a way that I could test your Spanish and German lessons? Quality is very important to me. Can you send me a lesson electronically (by email or word)? Maybe you have your lesson ready.