A、To tour the most famous sights of interest in China. B、To investigate the computer market in China. C、To negotiate a contract

W: Sit down, please, Mr. Black. I hope you enjoyed your journey.  
M: Of course, I did. It was a wonderful trip.
W: And I suspect this morning we’d like to get down to business. How would you like to proceed with the negotiations?
M: I’m here at your disposal.
W: Let’s draw up an agenda for our discussion, shall we?
M: Fine. One of the items for our agenda would be the supply of computers to China in the second half of this year. [19]/[20]As you know, our current contract is about to expire, and we will need to discuss a new one.  
W: Certainly, we are ready to hear your proposals.
M: Something else I’d like to discuss is the possibility of establishing a long-term agreement between my corporation and yours.
W: Yes. So long as it’s in the interest of both sides, let’s talk about it. Is there anything else you’d like to achieve on this visit?
M: Yes. [20]I’d like to build on the fact that we have had a very cooperative relationship in the past few years. Your government now has a policy of opening up to the outside world. My ambition is to promote trade between our two corporations. It is said a new policy is being put into practice in your foreign trade. Is that true?
W: Yes, but we still stick to a consistent policy in our foreign trade. [21]We insist on the principle of equality and mutual benefit, as well as exchanging needed goods.
M: Would you give us a brief account of the new practices you have adopted?
W: [22]We have adopted, for example, payment by installments.  
M: We are very glad that you have such a friendly attitude.
W: It’ll benefit both of us.
19. What’s the main purpose of the man’s visit?
20. What can we learn about the relationship between the two speakers?
21. What’s the woman’s principle in foreign trade based on?
22. What new practice has been adopted by the woman’s company?