This passage is mainly about the development and safety of robots.

A．simply withdraws to his own house
B．may still stay with his companion
C．retreats physically and mentally
D．doesn't talk as much as usual

A．the Japanese prefer crowding to privacy most of the time
B．space doesn't mean emptiness in the eyes of the Japanese
C．the Japanese dislike invasion of privacy in his house
D．the American require more space than the Japanese