Black Box
You never see them, but they're with you every time you fly. They record where you're going,how fast you're traveling and whether everything on your airplane is functioning normally. Their ability to resist almost any disaster makes them seem like something out of a comic (漫画)  book.They're known as the black box.
When planes fall from the sky, as a Yemeni airliner did on its way to the Comoros Islands in the Indian Ocean on June 30, 2009, the black box is the best method for identifying what went wrong. So when a French submarine(潜水艇)  discovered its homing signal five days later, it marked a huge step toward determining the cause of the disaster in which 152 passengers were killed.
In 1958. Australian scientist David Warren developed a flight-memory recorder that would track basic information like altitude and direction. That was the first model for a black box, which became a requirement on all US commercial flights by 1960. Early models often failed to resist crashes, however, so in 1965 it was completely redesigned. That same year, the Federal Aviation Authority required that the boxes, which were never actually black, be painted orange or yellow to be easier to see.
Modem airplanes have two black boxes: a voice recorder, which tracks pilots' conversations, and a flight-data recorder, which monitors fuel levels, engine noises and other operating functions that help experts reconstruct the aircraft's final moments. The boxes can resist powerful force and temperatures up t0 2,OOOoF. They're also able to send out signals from depths of 20,000 ft. Experts believe the boxes from Air France Flight 447 ,  which crashed near Brazil on June 1 , 2009 ,  are in water nearly that deep, but statistics say they're still likely to turn up. In the approximately 20 deep-sea crashes over the past 30 years, only one plane's black boxes were never recovered.
What can we leam about the black box from the passage?

A．It helps an airplane function normally.

B．Its ability to avoid disasters is amazing.

C．It is necessary equipment on an airplane.

D．The idea for its design comes from a comic book.

From the black box on the Yemeni airliner we can get information about _____.

A．the scene of the crash and the damage

B．data for analyzing the cause of the crash

C．the total number of passengers on board

D．homing signals sent by the pilot before the crash

The Federal Aviation Authority required the black boxes be painted orange or yellow to

A．make them easily identified

B．meet the international standards

C．caution people to handle them with care

D．distinguish them from the color of the plane

What do we know about the black boxes from Air France Flight 447?

A．They have stopped sending homing signals.

B．They were destroyed somewhere near Brazil.

C．There is an urgent need for them to be restructured.

D．There is still a good chance of their being recovered.