阅读下文，掌握其大意，然后从各题所给的四个选项中选出一个最佳答案。
Three1ago, my family got our first computer. 2 the beginning of this summer, I found it was too old and I wanted to get a 3 one. After my father and I talked for a long time, he 4 . We went to many shops and read many ads 5 we bought an HP computer.
During the first week, I noticed 6 our computer had some problems. I spent many hours 7 to fix it, but it 8 work. So I 9 to phone the HP company and ask them 10 to work out my problem. They told me to wait until the next morning because all their workers were 11 that day.
The next morning two workers came. It took them many hours to mend it, but the computer 12 did not work. My dad had no other way but to return the whole thing. A few days later, we decided that I should go on the Internet and order some parts to build a new computer by 13 .
It was not an easy job for me to build a new computer. I tried many times, and in the end I was successful. From these setbacks(挫折), I have learned a lot. Now I believe that if the HP computer hadn't had any problems, 14 I would not have learned how to build the new one. Even though I spent lots of time on it, I know it wasn't 15.
LaNi5+6Ni(OH)2