阅读下面短文，掌握其大意，然后从各题所给的A、B、C和D项中，选出最佳选项。
I met Mrs. Neidl in the ninth grade on a stage-design team for a play and she was one of the directors. Almost instantly I loved her. She had an unpleasant voice and a direct way of speaking,1she was encouraging and inspiring. For some reason, she was impressed with my work and me.
Mrs. Neidl would ask me for my2. She wanted to know how I thought we should3things. At first I had no idea how to answer because I knew4about stage design! But I slowly began to respond to her5. It was cause and effect: She believed I had opinions, so I began to6them. She trusted me to complete things, so I completed them perfectly. She loved how7I was, so I began to show up to paint more and more. She believed in me, so I began to believe in myself.Mrs. Neidl's8that year was, "Try it. We can always paint over it9!"I began to take10. I had been so afraid of failing but suddenly there was no failing-----only things to be11upon. I learned to dip my brush into the paint and 12create something.
The shy, quiet freshman achieved success that year. I was13in the program as "Student Art Assistant" because of the time and effort I'd put in. It was that year that I14I wanted to spend the rest of my life doing stage design.
Being on that stage-design team15Mrs. Neidl changed me completely. Not only was I stronger and more competent than I had thought, but I also16a strong interest and a world I hadn't known existed. She taught me not to17what people think I should do: She taught me to take chances and not be18. Mrs. Neidl was my comforter when I was upset. Her19in me has inspired me to do things that I never imagined20.
，工业上选择的适宜条件为：
、铁作催化剂、
。下列说法正确的是