A、By keeping silent. B、By speaking loudly. C、By walking quickly. D、By standing still. B男士说要想吓跑熊，可以在还没太靠近之前就制造响声，接着女士说下次她去野营时，她会一

W: Hi, Jack. How was the camping last week?
M: Oh, it was horrible. We nearly got killed.
W: What happened?
M: Well, [19]when we were walking on the path along one of the hills a bear suddenly jumped put of a bush and started to chase us.
W: That’s terrible. Did anybody get hurt?
M: Fortunately, we ran away before the bear got closer. We all agreed that we had never run so fast in our whole lives.
W: So why did the bear try to attack you? Was it hungry and looking for food?
M: No, it was more horrible. We later found out that the bear was a mother. And she was separated by us from her baby. She jumped out because she feared that her kid would get hurt. After the camping we learned not to get between an adult and any young bears.
W: But how could you make sure that you can see the bears? Supposed the mother and the children are hidden in a bush?
M: Well, it’s actually easy to avoid encounter with bears. They are shy animals and normally avoid human beings. In most of the cases they attack because they are shocked by the unexpected presence of human. What you have to do is to scare them away by making noises before you get too close.
W: I see, so next time when I go camping I’ll sing aloud when I’m walking.
M: That’s a good idea.
19. What happened during the man’s camping?
20. Why did the mother bear jump out?
21. Why do bears attack people?
22. How to scare bears away before getting too close?