17. W: Jim, I'm having difficulty with all the theoretical stuff we are getting in our computer course.
M: Oh, that part I understand. What I can't figure out is how to make it work in my program.
Q: What is the man's problem?

解析：D。男士说他不知怎样在程序中运用（理论），C中的"apply the theory to the program"正是男士所说内容的同义表达。所以答案为D。

18. M: I must point out that trials of new medicine are expensive, and you can never guarantee success.
W: But there is a very good chance in this case. I do hope you will go ahead in view of the potential benefit to mankind.
Q: What are the two speakers talking about?

解析：B。男士认为新药的试验费用很高，而女士则说：“我真的希望您考虑到它可能给人类带来的好处而继续研究下去。”可知他们在讨论新药。答案为B。