To encourage students at our school to use the library, the instructors developed a worksheet to encourage students to use the book in the library to find the answer. We are a machinist school and in the industry students will be expected to determine speeds and feeds to name a few of the things the look up. Also, the career service department has books on the types of positions they can find in the machining industry. There are books about resumes, interview techniques, and so. All of this is done to encourage students to utilize the library. 

This has happened to me before, what I did was pause then came up with a way to make it more relatable to the audience. Another approach would be to put more energy into the presentation and use visuals and ask opened ended questions to involve the audience more.