Question 16 is based on the passage you have just heard.

    (16) There are a few differences in the organization of memorandums and letters. Memorandums and letters differ somewhat in appearance. “To” and “From” replace a letter’s inside address and signature block, for example. Further, letters are usually sent outside the organization, while memorandums are usually internal messages. As internal messages, memorandums tend to be more informal and more direct than their letter counterparts. (17) One survey of 800 business people showed they spent from 21 to 38 percent of their time writing memorandums. There must be a lot of executives overwhelmed by the number of memorandums they received. As a result, (18) competition for the readers’ time places importance on directness and clarity in memorandums, so perhaps even more so than with letters. Memorandum should start with a statement of the purpose early in the message. Memorandums also need special visual treatment: keep paragraphs short, much like newspaper articles. Computers increasingly aid mid and upper level managers who prepare their own memorandums without secretarial help. If you prepare your own correspondence, realize the importance of dating your messages. Knowing precisely when you recommended, ordered, signed or asked about something often is crucial. Computers often can date information for you easily. Another characteristic that can set memorandums apart from letters is the inclusion of humor. When the internal message is light-hearted and relatively unimportant, (19) humor in a memorandum can distinguish its author as a person with personality and depth. As long as the humor is on target, does not embarrass others, is not overdone, and is not too frequent, it can reflect positively on its author.

16. How does the speaker start his talk?

正确答案：C

解析：短文开头提到，备忘录和信件的结构有些差异。即，说话者以备忘录和信件的对比开始。