5. Break through the "fourth wall." Ever take a course in college where you never knew when the instructor was going to call on you, out of the blue, and expect some intelligent comment? It's a time-honored technique for keeping an audience on its toes, since no one wants to be caught napping (literally or metaphorically), and it works for speeches, too.

5. 突破“第四面墙”。你有没有过这样的经历——在大学上课，不知道导师什么时候会突然点到你的名字，希望你能给出一些聪明的评论？这种历史悠久的技巧可以让听众时刻保持紧张，因为没有人希望在毫无防备的情况下被抓突然提问，这种技巧同样适用于演讲。

"Involve your listeners by encouraging constructive interruptions, like questions," O'Brien suggests. "Or pick people in the audience at random, and ask them to weigh in."

奥布莱恩建议：“通过鼓励听众建设性地打断演讲，比如提出问题等，让听众参与其中。或随机挑选听众，邀请他们参与讨论。”

Some expert speakers, like former GE (GE) chief Jack Welch, have made use of Twitter to let audience members Tweet a constant stream of questions and comments, which Welch then addresses in real time. It's not a technique for the faint of heart, but it does keep people's attention from wandering. These days, that's no small feat.

有一些演讲大师，比如前通用电气（GE）首席执行官杰克•韦尔奇，会利用Twitter，让听众们提出问题和评论，韦尔奇会实时进行解答。这种技巧不适合胆小的人，但确实能让听众们集中注意力。这在当今可谓是不小的壮举。