Postmates, an American delivery company, has built a robot, called Serve, which was designed to make short-distance deliveries in cities.

To know what's going on, Serve has a laser radar （激光雷达）sensor on top, in which spinning lasers let it detect objects around it and know how far away they are. Also, behind each artificial eye is a camera, with six more imaging devices spread around the robot. Inside it is another sensor that allows Postmates to know if there is a package in there.

“One of our key decisions early on was to rely heavily on the robot’s ability to see the environment,” says Ali Kashani, the vice president for robotics at Postmates. Since the sidewalk is “a very chaotic environment”，he points out, the robot needs to be able to take it all in and figure out what to do. This robot, and many like it, also must be able to signal their intentions to the pedestrians. For that，it has a number of approaches. One is using its eyes; another is a colorful light ring that goes around the top. “When it wants to make way for a pedestrian, it will use its eyes and look down，” he explains. It can also use the lights on the top as a turn signal，which is obvious, and also look left and right when it’s turning left and right.

Using eye movements and other silent signals is a good idea，” says Aaron Steinfeld, a professor on human-robot interaction （互动）.Serve is intended for sidewalks * and Steinfeld says that environment is challenging. People usually walk fast while staring at a smartphone. For a robot，that’s a lot. “We have active research on robot moving socially around walking people,” he says. “And it，s really tricky to do this well. ”

Postmates plans to use Serve in Los Angeles at first, and that its intended task is to move small objects over short distances”. The robot can travel 30 miles on one charge and is able to carry 50 pounds.

【小题1】What was Serve designed for?

A．Object detection.

B．Package transportation.

C．Environment protection.

D．Short-distance communication.

【小题2】What is challenging to Serve?

A．Moving objects.

B．Sending silent signals.

C．Sidewalk environment.

D．Pedestrian recognition.

【小题3】What does the underlined word “that” in Paragraph 3 refer to?

A．Calling other robots.

B．Signaling to the people nearby.

C．Making way for the pedestrians.

D．Turning on the colorful light ring.

【小题4】What is the author’s purpose in writing the text?

A．To introduce a new robot.

B．To explain human-robot interaction.

C．To present different opinions on hi-tech.

D．To advertise an American delivery company.