阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
A
Robert Downey Jr. is famous for being a beloved Hollywood actor, but now he is adding “robotics environmentalist” to his list of good qualities. Earlier this week, the IronMan actor went to the Amazon Mars Conference in Las Vegas to announce the creation of his new foundation which would use nanotechnology (纳米技术) and robotics as a means of cleaning up the planet.
Downey Jr. did not show many details on how the organization would begin its cleanup job, but a website went live shortly after the actor's announcement. As of right now, the website only includes a signup sheet for future newsletters and latest news. But Downey Jr. said that he would be spending the next 11 months working together with UN experts and building up the organization so the group could get to work by April 2020.
After that, Downey Jr. said that “Between robotics and nanotechnology we could clean up the planet significantly, if not totally, in ten years.” Downey Jr. also explained how his failure to look after the environment in the past is now inspiring him to take action. “I have this quiet sense of crisis (危机)，” he said. “I used to spend a lot of energy on things like plane trips, but I want to change.” Regardless of the actor's plan, Downey Jr.'s net worth is about $ 81 million—more than enough to start tidying up the planet.
The Amazon Mars Conference, which stands for “Machine learning, Automation, Robotics and Space” , hosted a lot of speakers who gave lectures on the benefits of artificial intelligence. In addition to announcing the start of his organization, Downey Jr. also talked about how he and his wife Susan would be the managing producers of a new documentary series on the wonders of AI.
21．Downey Jr. set up the foundation in order to ________．
A.release his newlymade film IronMan officially
B．devote his spare time to environmental protection
C．inspire his crazy fans not to damage the environment
D．raise enough money to make films with high technology
22．What can be inferred from the text?
A．Downey Jr. founded his organization while making his film.
B．Downey Jr. joined in cleaning up the planet ten years ago.
C．Downey Jr. regretted not leading a greener life in the past.
D．Downey Jr. hosted a live conference on AI on the Internet.
23．Which of the following can best describe Downey Jr. in the text?
A．Environmentally friendly. B．Generous.
C．Warmhearted. D．Popular.
