A、Psychologists. B、Police officers. C、Room cleaners. D、Doctors. C

(19) Robots should be taxed at the same level as the people they replace, to help fund better social services and education, according to Microsoft co-founder Bill Gates.
    Governments rather than businesses need to take the lead on managing the robotics revolution and ensuring there’s a plan to deal with the unemployed workers it creates over the next 20 years, Gates told Quartz.
    "Right now, if a human worker does $50,000 worth of work in a factory, that income is taxed. If a robot comes in to do the same thing, you’d think we’d tax the robot at a similar level," he said.
Automation probably won’t lead to massive unemployment, but governments will still need to prepare for major changes, according to a new study. (20) Also, with fewer people working, governments will have less income tax to spend at a time when it may need more money rather than less.
    Gates argues that governments should raise taxes on robots to slow down adoption and provide the time needed to devise programs that create a net benefit from this excess labor.
    (21) "You cross the threshold of job-replacement of certain activities—warehouse work, driving, room cleanup. Certainly, in the next 20 years, being thoughtful about that extra supply is a net benefit. It’s important to have the policies to go with that," Gates said.
Questions 19 to 21 are based on the passage you have just heard.
19. What does Bill Gates say about robots?  
20. What will happen to governments with the adoption of automation according to a new study?  
21. What kind of workers will probably be substituted by robots in the future according to Gates?