A、He didn’t like physics any more. B、His eyesight was too poor. C、Physics was too hard for him. D、He had to work to support hims

When I was at school, my ambition was to be a pilot in the Air Force. But my eyesight wasn’t good enough. So I had to give up that idea. I went to university and studied physics. I wanted to stay on there and do research. [19] But my father died at about that time. So I thought I’d better get a job and earn my living. I started working in an engineering firm. I expected to stay in that job for a long time. [20] But then, they appointed a new managing director. I didn’t get on with him, so I resigned and applied for a job with another engineering company. I would certainly have accepted the job if they had offered it to me. But on my way to the interview, [21] I met a friend who was working for a travel agency. He offered me a job in Spain. And I had always liked Spain, so I took it. I worked in the travel agency for two years and then they wanted to send me to South America. But I had just got married. So I decided to stay here. [22] Then we had a baby and I wasn’t earning enough to support the family. So I started giving English lessons at a school in the evening. I liked English teaching more than working for the travel agency, and then the owner of the school offered me a full-time job as a teacher. So I resigned from the agency. Two years later, the owner of the school wanted to retire, so he asked me to take over as the director. And here I am.
Questions 19 to 22 are based on the passage you have just heard.
19. Why did the man give up studying physics?
20. Why did the man resign from the engineering firm?
21. Why did the man take the job at the travel agency?
22. Why did the man start to teach English part-time?