题目内容：

    The dangers of drowsy（昏昏欲睡） driving have been widely known. Now several companies have developed face-tracking technology that can tell when drivers become dangerously sleepy.

Here is how it might work. A camera in your car monitors your facial expression, compares it to a database of expressions and determines if you are likely sleepy or distracted. The car then alerts you to pay attention or pull over.

Affectiva has developed emotion recognition technology that aims to detect when people are just starting to get tired. The idea is to catch the warning signs before drowsiness really strikes. “Actually, when someone is drowsy, that is too late.” Gabi, vice president of Affectiva said. “What if you can see trends in someone’s face about five minutes before they become sleepy?” Affectiva’s program can recognize seven different emotions and 15 facial expressions. Its standards were developed by sifting （筛选） through a database of 4 million faces from 75 countries, said Zijderveld. She suggested that carmakers could coordinate （协调）the program’s facial recognition data with oral reminders, such as sound warnings, or （nonverbal）alerts, like a change of temperature and vibrations （continuous slight shaking movements）.

Eyeris is another company working in facial analytics. Modar Alaoui, the company’s CEO, said that its software detects “eye openness” in addition to other facial indicators. The software can also read head position, which may indicate when someone begins to nod off.

These technologies aren’t the first attempt to fight drowsiness behind the wheel. Inventors came up with the similar device “sleeper beeper” to prevent sleep in cars back in 1983. The sleeper beeper was attached to a driver’s ear and would issue a noisy warning when the driver’s head nodded past a certain point. But the latest software would intervene （干涉） earlier and more effectively.

1.The camera in the car can determine if a driver is ________.

A. cold-blooded B. near-sighted

C. bad-tempered D. absent-minded

2.When will drivers be reminded to pay attention or pull over by the face-tracking technology?

A. When they are just beginning to get tired.

B. Five minutes after they become sleepy.

C. When they are really tired.

D. When they are drowsy.

3.It is most likely that the “sleeper beeper” would send out a warning by ________.

A. shaking slightly B. making noise

C. flashing brilliantly D. changing temperature

4.What is the main idea of the text?

A. The dangers of drowsy driving have been widely known.

B. Inventors have tried out the similar device “sleeper beeper”.

C. Several companies have found some ways to fight drowisness behind the wheel.

D. Face-tracking technology for drowsy driving has been developed by several companies.