题目内容：

Science is always advancing over time. A self-driving car from the Google may be coming to a street near you. However, you won’t be able to buy it now. “We’re working to build the world’s most experienced driver,” Kraft, director of the project, said. “Everything that we learn in one of our cars gets passed to all of our cars. But you may need to get over the idea of traditional car ownership along the way.”

Google’s software has already driven 5 million miles in U.S. cities, including an “early rider” test in Phoenix last April. Since then Google has grown confident enough to remove the “auxiliary wheel”: a human “safety driver”. Powering the vehicle’s self-driving functions is a series of cameras, radars and sensors on the car’s roof, which detect everything nearby from other vehicles and passers-by to cyclists.

Kraft stressed that Google’s cars aren’t connected—they don’t need a 5G wireless link to go anywhere. “The car has everything it needs to drive on the car itself.” He said, “There are no signals coming from outer space or something telling it to turn right.” The resulting ride may not be too exciting but safe. Kraft added. “We can see three football fields down the road, we would come to a stop before we ran into these crowds.”

Google’s system has a major advantage over the semi-autonomous（半自主的）systems of Tesla and Cadillac, both of which need continued human attention. Kraft said Google plans to have service in every major city by 2028 with thousands of cars driving themselves.

1.What does the underlined words “auxiliary wheels” in Paragraph 2 refer to?

A. A car that is very old.

B. A driver who has been trained well.

C. A part of a car used to sound the alarm.

D. A condition where a driver doesn’t know his role.

2.Why is Google’s car thought to be safe in the text?

A. Because it can get away from danger easily.

B. Because it is equipped with 5G wireless link.

C. Because it can stop before the crowds occasionally.

D. Because it can keep a safe distance from everything nearby.

3.What can we learn from the text?

A. Google’s software has not been tested.

B. Google’s cars have not been put into the market.

C. Driving the Google’s car may not be too exciting.

D. Google’s cars still need driver’s attention all the way.

4.What does the author think of the Google’s car?

A. It’s affordable.

B. It’s still a theory.

C. It has a bright future.

D. It’s the most advanced by now.