题目内容：

    To move visual technology into the future, sometimes it helps to make a little noise. Researchers have used sound waves to produce floating 3-D images, create a sense of touch and even supply a soundtrack.

Since the 1940s, scientists have toyed with the concept of acoustic levitation(声悬浮), the use of soundwave vibrations to trap tiny things in midair. The technology has gained greater capabilities in the past decade. Some researchers believe this improvement could lead to applications such as contributing to novel 3-D printing methods, or creating displays that would be visible from any angle without requiring a screen.

Other researchers have also worked on visual displays that use acoustic levitation. In addition to visuals, the system can also produce audible noise to give the display a soundtrack. And the ultrasound speakers can also concentrate vibrations in one spot so that a finger might feel a sense pushing back—a little like the object shown by the floating image is really there. Soundwaves create a 3-D display!

Display without a screen is remarkably useful. It means that everybody in the room can see the image—any angle, location—and that’s extremely helpful. As a communications system, such a display might one day allow users to chat with a 3-D projection(投影) of a person who can turn his or her head to follow as they move around a room.

The display will require a lot more work before you can install it in your living room, however. So far, this has been done in the research laboratory. We need to push it a little bit harder. We need to do more analysis to see if it would make sense to create a real display that people would have at home. The current system can only show simple graphics, such as a smiley face or figure eight, in real time.

Still, we are optimistic about the potential for this type of technology. If the system had only one speaker-covered surface instead of two, it could generate images that are bigger than the device itself. We can’t make a TV image that’s bigger than the TV—even a projector has to have a projection screen that’s bigger than the image itself. But with a volumetric(容积的) display, a small, portable device might produce a much larger picture. We can imagine, in the future, having volumetric displays in watches, for example, that create large images that just project out of your watch.

1.From the first two paragraphs soundwave vibrations can be used to _________.

A.catch very small objects in midair

B.develop 3-D printer’s capabilities

C.replace a creative display screen

D.compose soundtracks by making no noise

2.What do we know about display without a screen?

A.It has resulted in visual technology.

B.It is possible to see the image from any direction.

C.It is already ripe to create a real one at home.

D.It has yet to be tested in the research laboratory.

3.What does the last paragraph mainly talk about?

A.Outlooks for the new technology.

B.Situations of the modern technology.

C.Praise for the cutting-edge technology.

D.Room for the technical improvement.

4.What can be a suitable title for the passage?

A.Hearing Is Seeing—Sound Waves Create a 3-D Display

B.Seeing is Believing—3-D Printing Methods Arrive

C.Advancing Sense of Touch—3-D Images Float in the Air

D.Promoting TV Technology—Chat with 3-D Projections