humor本题也可以通过听前预测帮忙，既然前面是sarcasm，后面应该是某种修辞方法。综合而言，此题的答案比较容易写对，因为短文用了大量的主题句(top sentences)，文章内容就非常清楚

If you work in the business world, email is undoubtedly a big part of your life. Yet few of us who rely on email as a mode of communication even took a course in its proper use. Below are some tips for you to improve your digital messages and ensure that your electronic correspondence fosters good relations rather than hard feelings.
    1. In an email message, never say something about someone else that you would not want that person to see. Keep in mind that email messages can be forwarded to anybody by the recipient. Therefore, never say something in an email that you would be embarrassed to have read back to you.
     2. Get the most out of your subject line. Remember that aside from your name, the subject line of your email message is the first thing that a recipient will read. So it pays to take some time to think about your subject line.
     3. Do use commonly accepted standards of manners in all email messages that you send. Avoid using all capital letters in your message, which may, well give one the impression that you are screaming. In addition, be careful about any use of sarcasm or humor in your email messages. In writing, both sarcasm and humor can easily be misinterpreted.
    4. Before sending an email message, consider whether email is the most effective form of communication for your purpose. In business settings, email is best used to convey key information, to confirm appointments, to document decisions, or to contact a decision maker directly.
     Avoid using an email message to begin a conversation that likely will require input from several people at the same time unless the decision-making process should be documented. At last, remember the value of face-to-face conversation.