41. D

public nuisance (n): a person or thing that annoys a lot of people (mối phiền toái)

42. A

performing (adj): trained to perform tricks before an audience, as in a circus. (đã qua huấn luyện, thường thấy ở rạp xiếc)

43. D

retrieve (v): bring or get something back, especially from a place where it should not be (tìm lại, tìm và mang về)

44. A

pen (n): a small piece of land surrounded by a fence in which farm animals are kept

Ex: a sheep pen (chuồng cừu)

45. D

buzz (v): to make a continuous low sound (tiếng vo vo)

46. A

habitat (n): the place where a particular type of animal or plant is normally found (môi trường sống của động/thực vật)

47. B

on the alert: cảnh giác

48. C

abound in/with sth: to have sth in great numbers or quantities (có rất nhiều...)

49. B

give sb the creeps (idiom): làm ai đó sởn tóc gáy

50. D

nibble on/at sth: to take small bites of something, especially food (gặm, nhắm, rỉa)