Why do human beings still risk their lives under ground and doing one of the dirtiest and most dangerous jobs in the world？A small group of engineers and robotics experts envision(展望) a day in the not-too-distant future when robots and other technology do most of the dangerous mining work.

One of the first mining robots was developed five years ago at Carnegie Mellon University's Robotics Institute. It was called Groundhog and it looked like a golf cart. It used lasers(激光) to “see” in dark tunnels and map abandoned mines－some of the most dangerous work in the business.
The latest prototype is called Cave Crawler. It's a bit smaller than Groundhog，and even more advanced. It can take photos and videos and has sensors that can detect the presence of dangerous gases. Incredibly，the robot has a real sense of logic. If it comes across an obstacle it gets momentarily confused. It has to think about what to do and where to go next. Sometimes it throws_a_fit just like a real person.
Myles and his colleagues hope that robots like Cave Crawler will one day be used in rescue operations. “A robot could speed up the rescue process by doing reconnaissance(侦察)，” says Chuck Whittaker，a robotics engineer at Carnegie Mellon. “The robot can go ahead and，with its sensors，report what it has found and whether it is safe for humans to proceed.”
Using robots in rescue operations，though，is problematic. The lasers that guide the robots don't work in smoky environments so the engineers at Carnegie Mellon have experimented with sonar(声呐)and radar guidance systems，and with some success.
Some experts predict that robots in mines will serve much of the same function that they do in the automotive industry. The robots do the most repetitive and dangerous jobs，but won't get rid of the need for human workers.
The underlined phrase “throws a fit” in Paragraph 3 probably means ______.

A．gets angry

B．gets shocked

C．becomes confused

D．becomes cheerful

The latest robot is more advanced than Groundhog mainly because ________.

A．it can map abandoned mines

B．it can see in the dark tunnels

C．it's smaller than Groundhog

D．it has a real sense of logic

We can infer from the last paragraph that ________.

A．the mining robots will have a very bright future

B．robots in the automotive industry must be improved

C．there will be no need for human workers in mines

D．robots in mines will cost a lot

What can guide the robots in smoky environments?

A．The lasers.

B．Sonar and radar guidance systems.

C．Command guidance systems.

D．Image matching guidance systems.