填空题

May 8th, 2005
Dear Mr. Steele,
We are writing in reply to your letter of April 5th, in which you asked for our advice concerning the marketing of motor-cycles in the western part of your country.
At the moment, it would seem to us that it is not possible to give a definite answer about the prospects for such a plan. This is especially so, since there are such vast differences between the various places in that part of your country. It would appear to us that your best way is to conduct an area sales survey. In addition to the survey, we also advise you to make a personal visit to those places. This would enable you to know more about local economic environment to conduct the sales survey. It is quite vital for planning a major marketing venture.
We hope you can accept our suggestion and look forward to hearing from you again in the near future.
Yours sincerely,
C. Brown
What advice did Mr. Brown give him
The best way is to conduct a(n) ______.