17
A. Traveling to different places in the world.
B. Playing games that challenge one’s mind.
C. Improving mind-reading strategies.
D. Reading classic scientific literature.
18
A. Participate in debates or discussions.
B. Expose themselves to different cultures.
C. Discard personal biases and prejudices.
D. Give others freedom to express themselves.
19
A. Why dogs can be faithful friends of humans.
B. The nature of relationships between dogs.
C. The reason a great many people love dogs.
D. How dogs feel about their bonds with humans.
20
A. They behave like other animals in many ways.
B. They have an unusual sense of responsibility.
C. They can respond to humans’ questions.
D. They can fall in love just like humans.
21
A. They stay with one partner for life.
B. They have their own joys and sorrows.
C. They experience true romantic love.
D. They help humans in various ways.
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