Registrar unfortunately the computers usually pretty

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Registrar Unfortunately, the computer’s usually pretty reliable … so I’m not sure what’s going on here. Narrator What does the registrar imply when she says this: Registrar Unfortunately, the computer’s usually pretty reliable … so I’m not sure what’s going on here. APPENDIX B
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TOEFL iBT ® Quick Prep 32 Listening Practice Set 2: Transcript for Track 3: Narrator Listen to part of a lecture in a biology class. Professor So, that’s how elephants use infra sound … Now let’s talk about the other end of the acoustical spectrum—sound that’s too high for humans to hear: ultra sound. Ultrasound is used by many animals that detect—and, some of them, send out—very high-frequency sounds. So, what’s a good example? Yes, Carol? Female Student Well, bats—since they’re all blind, bats have to use sound for—uh, y’know—to keep from flying into things. Professor That’s echolocation. Echolocation is pretty self-explanatory: Using echoes—reflected sound waves—to locate things … As Carol said, bats use it for navigation and orientation … and what else? Mike? Male student Well, finding food is always important—and, uh, I guess, not becoming food for other animals … Professor Right on both counts. Avoiding other predators—and locating prey—uh, typically insects that fly around at night. Now, before I go on, let me just respond to something Carol was saying—this idea that bats are blind … actually, there are some species of bats—the ones that don’t use echolocation—that do rely on their vision for navigation but, it is true that, for many bats, their vision is too weak to count on. OK, so: quick summary of how echolocation works. The bat emits these ultrasonic pulses—very high-pitched sound waves that we can’t hear—and then: APPENDIX B
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TOEFL iBT ® Quick Prep 33 they analyze the echoes—how the waves bounce back. Uh, here, let me finish this diagram I started before class … So the bat sends out these pulses—very focused bursts of sound, and echoes bounce back … Y’know, I don’t think I need to draw in the echoes. Your-your reading assignment for the next class—it has a diagram that shows this very clearly—so anyway, as I was saying … By analyzing these echoes, the bat can determine, say, if there’s a wall in a cave that it needs to avoid … and—how far away it is. Another thing it uses ultrasound to detect is the size and shape of objects. For example, one echo they’d quickly identify is the one they associate with a moth, which is common prey for a bat— particularly, a moth beating its wings. However, moths happen to have a major advantage over most other insects: they can detect ultrasound. This means that, when a bat approaches, the moth can detect the bat’s presence … so it has time to escape to safety … or else they can just remain motionless—since, um, when they stop beating their wings, they’d be much harder for the bat to distinguish from, oh, a-a leaf … or-or some other object … Now, we’ve tended to underestimate just how sophisticated the abilities of animals that use ultrasound are. In fact, we kind of assumed that they were
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