Passage2

　　19 B They avoid looking at them.

　　20 C It focuses its eyes on their mouths.

　　21 B By taking in their facial expressions as a whole.

　　Passage3

　　22 D They resort to different means to survive the bitter cold.

　　23 C They consume the energy stored before the long sleep.

　　24 A By storing enough food beforehand

　　25 C To stay safe

　　选词填空答案

　　26.O vigorous

　　27.I phenomenon

　　28.E effectively

　　29.G involved

　　30.M solution

　　31.D cycling

　　32.C control

　　33. J preventing

　　34. N sufficient

　　35. F increased