45. What is this passage mainly about?
(A) West Nile and methods to fight it.
(B) West Nile and governmental efficiency.
(C) West Nile and the conditions its virus thrives in.
(D) West Nile and its relation to tropical diseases.

41. What is this passage mainly about? (A) The design of the White House. (B) The location of the White House. (C) The importance of the White House. (D) The history of the White House.

42. What does “this practice” refer to in the second paragraph? (A) Holding an inaugural open house. (B) Accommodating the crowds comfortably. (C) Decorating the White House. (D) Joining in the swearing-in ceremony.

43. Who initiated the construction of the White House? (A) John Adams. (B) James Hoban. (C) George Washington. (D) Thomas Jefferson.

44. According to the passage, which of the following is NOT true about the White House? (A) The White House has had several names. (B) The designer of the White House was an American president. (C) People were not allowed to visit the White House during wartime. (D) The White House is located in a district not larger than ten miles square.

46. Which of the following statements is true about West Nile? (A) Its symptoms usually appear within two weeks. (B) It is spread through air and water in tropical areas. (C) Over 20% of people who contract it will suffer severe symptoms. (D) It comes from direct human contact with birds infected with the virus.

47. What did Dallas County do to fight off West Nile? (A) They sprayed pesticide from the air. (B) They asked citizens to stay away from dead birds. (C) They encouraged citizens to get vaccinations. (D) They drained the swimming pools in the county.

48. Which of the following is a reason why Dallas was hit most seriously in the U.S. in 2012? (A) The increasing population in Texas raised the risk of contracting the disease. (B) The government did not issue a warning about the disease in time. (C) The residents worried about the county’s decision and action. (D) The weather of the previous winter was not as cold as usual.

49. Which of the following is closest in meaning to “arid” in the first paragraph? (A) Occupied. (B) Isolated. (C) Dry. (D) Remote.

50. What is the second paragraph mainly about? (A) The high cost of desalinating seawater. (B) The major chemical characteristics of seawater. (C) The urgent need to turn seawater into fresh water. (D) The amount of energy produced in the desalination of seawater.

51. According to the passage, which of the following statements is true? (A) Mixing salt with water is not as easy as removing salt from seawater. (B) Desalinating seawater may kill some sea creatures and disturb the food chain. (C) Covering 70% of the Earth, the ocean has always satisfied human needs for water. (D) The increasing population in Saudi Arabia has resulted in shortages of fresh water.