A、Unsuccessful. B、Rewarding. C、Tedious. D、Important. A短文中说Huang Yi工作的前几个月十分“困难”。他让客户觉得虽然他教了两个星期，但他的客户依然不会使用该财务软件。由此可知，他的工作并不成功。

Huang Yi works for a company that sells financial software to small and medium-size businesses. His job is to show customers how to use the new software. He spends two weeks with each client, demonstrating the features and functions of the software. The first few months in the job were difficult. He often left the client feeling that even after two weeks he hadn’t been able to show the employees everything they needed to know. It’s not that they weren’t interested; they obviously appreciated his instruction and showed a desire to learn. Huang couldn’t figure out if the software was difficult for them to understand, or if he was not doing a good job of teaching. During the next few months, Huang started to see some patterns. He would get to a new client site and spend the first week going over the software with the employees. He usually did this in shifts, with different groups of employees listening to him lecture. Then he would spend the next week installing the program and helping individuals trouble-shoot. Huang realized that during the week of troubleshooting and answering questions, he ended up addressing the same issues over and over. He was annoyed because most of the individuals with whom he worked seem to have retained very little information from the first week. They asked very basic questions and often needed prompting from beginning to end. At first, he wondered if these people were just a little slow, but then he began to get the distinct feeling that part of the problem might be his style presenting the information.
19. What does Huang Yi do in his company?
20. What did Huang Yi think of his work?
21. What did Huang Yi do in addition to lecturing?
22. What did Huang Yi realize in the end?