41. Why do howler monkeys howl?
(A) To claim their territory.
(B) To check how popular they are.
(C) To tell others they are going to leave.
(D) To show friendliness to their neighbors.

37.(A) screamed (B) learned (C) recognize (D) stroke (E) sharpened

38.(A) screamed (B) learned (C) recognize (D) stroke (E) sharpened

39.(A) shock (B) conversation (C) like (D) promise (E) released

40.(A) shock (B) conversation (C) like (D) promise (E) released

42. Why did the howler monkeys in Belize howl less often? (A) They lived too close to each other. (B) There was enough food for all of them. (C) There were no other competitors around. (D) They were not used to the weather there.

43. Why do the keepers at the sanctuary use recorded howls? (A) To prevent the howler monkeys from getting homesick. (B) To help howler monkeys maintain their howling ability. (C) To trick the monkeys into the belief that there is plenty of space around. (D) To teach the monkeys how to make the loudest cries to scare people away.

44. According to the passage, which of the following is true about howler monkeys? (A) They howl most often at noon. (B) They originally came from Belize. (C) People can hear their howls three miles away. (D) Female monkeys howl to protect their babies.

45. What made it necessary to build a road through the Glacier National Park? (A) There were too many parks in Montana. (B) The park was not sunny enough for visitors. (C) The existing mountain roads were destroyed. (D) More visitors were interested in going to the park.

46. How has the Going-to-the-Sun Road influenced the way people experience the Glacier National Park? (A) The scenery along the road is too beautiful for visitors to drive carefully. (B) It has become a marvelous experience for people to ride horses on this road. (C) The road has allowed people to see more of the park in a shorter period of time. (D) The transportation on the road was so difficult that few people could really enjoy the trip.

47. What does “an engineering feat” mean? (A) A big success in construction. (B) A magical building machine. (C) A great disaster for the travelers. (D) An enjoyable process for engineers.