45. Why is the value of Bitcoin not stable?
(A) Because its use is illegal.
(B) Because it is not a valid investment.
(C) Because it is still developing.
(D) Because its circulation is limited to the youth.

41. Which of the following is a finding of the two American professors’ study? (A) Many Japanese men that lived up to 100 years were smokers. (B) Those who often ate hamburgers and fries were more likely to fall sick. (C) Japanese immigrants to America usually formed a tight-knit community. (D) Westernized social life was related to the heart-attack rate of Japanese Americans.

42. Which of the following is an example of “something bigger” in the last paragraph? (A) A family. (B) A stadium. (C) The universe. (D) The digital world.

43. What is the ratio of heart disease between Japanese living in Japan and Japanese Americans in Hawaii? (A) 1 to 2.5 (B) 1 to 5 (C) 3 to 5 (D) 1.5 to 5

44. What is the purpose of this article? (A) To introduce a new currency. (B) To prove the value of a young economy. (C) To explore ways to do online transactions. (D) To explain how to build up a business network.

46. Which of the following is true about Bitcoin? (A) Bitcoin addresses are known only to their owners. (B) Once a transaction is made, the Bitcoin cannot be refunded. (C) Bitcoin user’s identity is always open to the general public. (D) When a payment is received, the Bitcoin can be turned into local currency.

47. What advice would the author give to those who are interested in keeping money in Bitcoin? (A) Better late than never. (B) Look before you leap. (C) Make hay while the sun shines. (D) No pain, no gain.

48. What is the main idea of this passage? (A) Researchers have found an effective way to halt the spread of insect-borne diseases around the world. (B) Many people are worried about the effects of genetically modified organisms on the environment. (C) It takes time to gain public support for the application of genetic modification to disease control. (D) Genetic engineering looks promising in reducing malaria, though there may be unknown consequences.

49. Which of the following best shows the organization of this passage? (A) Introduction => Comparison => Contrast (B) Problem => Solution => Potential difficulties (C) Proposal => Arguments => Counter-arguments (D) Definition => Examples => Tentative conclusions

50. According to the passage, which of the following is true about malaria parasites? (A) They are resistant to genetic modification and vaccines. (B) They reproduce in the human liver and grow stronger there. (C) They can be found in only one gender of a class of mosquitoes. (D) They are transmitted to around one million children each year.

51. What does “that” in the third paragraph refer to? (A) Some malaria parasites escaping from the ecosystems. (B) Malaria parasites becoming immune to the engineered bacterium. (C) Modified mosquitoes becoming more competitive than the wild ones. (D) Transmission of malaria being blocked from mosquitoes to humans.