Read the following passage and choose A, B, C or D to indicate the correct answer to each of the following questions from 38 to 42.

In this era of increased global warming and diminishing fossil fuel supplies, we must begin to put a greater priority on harnessing alternative energy sources. Fortunately, there are a number of readily available, renewable resources that are both cost- effective and earth - friendly. Two such resources are solar power and geothermal power.

Solar energy, which reaches the earth through sunlight, is so abundant that it could meet the needs of worldwide energy consumption 6,000 times over. And solar energy is easily harnessed through the use of photovoltaic cells that convert sunlight to electricity. In the us alone, more than 100, 000 homes are equipped with solar electric systems in the form of solar panels or solar roof tiles. And in other parts of the world, including many developing countries, the use of solar system is growing steadily.

Another alternative energy source, which is abundant in specific geographical areas, is geothermal power, which creates energy by tapping heat from below the surface of the earth. Hot water and steam that are trapped in underground pools are pumped to the surface and used to run a generator, which produces electricity. Geothermal energy is 50,000 times more abundant than the entire known supply of fossil fuel resources and as with solar power, the technology needed to utilize geothermal energy is fairly simple. A prime example of effective geothermal use in Iceland, a region of high geothermal activity where there are over 80 percent of private homes, are heated by geothermal power.

Solar and geothermal energy are just two of promising renewable alternatives to conventional energy sources. The time is long overdue to invest in the development and use of alternative energy on global scale. 

What is the main topic of this passage?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions from 43 to 50.

According to sociologists, there are several different ways in which a person may become recognized as the leader of a social group in the United States. In the family, traditional cultural patterns confer leadership on one or both of the parents. In other cases, such as friendship groups, one or more persons may gradually emerge as leaders, although there is no formal process of selection. In larger groups, leaders are usually chosen formally through election or recruitment.

Although leaders are often thought to be people with unusual personal ability, decades of research have failed to produce consistent evidence that there is any category of “natural leaders.” It seems that there is no set of personal qualities that all leaders have in common; rather, virtually any person may be recognized as a leader if the person has qualities that meet the needs of that particular group.

Furthermore, although it is commonly supposed that social groups have a single leader, research suggests that there are typically two different leadership roles that are held by different individuals. Instrumental leadership is leadership that emphasizes the completion of tasks by a social group. Group members look to instrumental leaders to “get things” done. Expressive leadership, on the other hand, is leadership that emphasizes the collective well¬being of a social group’s member. Expressive leader are less concerned with the overall goals of the group than with providing emotional support to group members and attempting to minimize tension and conflict among them. Group members expect expressive leaders to maintain stable relationships within the group and provide support to individual members. Instrumental leaders are likely to have a rather secondary relationship to other group members. They give orders and may discipline group members who inhibit attainment of the groups goals. Expressive leaders cultivate a more personal or primary relationship to others in the group. They offer sympathy when someone experiences difficulties or is subjected to discipline, are quick to lighten a serious moment with humor, and try to resolve issues that threaten to divide the group. As the differences in these two roles suggest, expressive leaders generally receive more personal affection from group members; instrumental leaders, if they are successful in promoting group goals, may enjoy a more distant respect.

What does the passage mainly discuss?

The passage mentions all of the following ways by which people can become leaders EXCEPT___________

It can be understood that___________

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.