54. What constitutes a major threat to the survival of turtles according to Elizabeth Griffin?

A) Their inadequate food supply.

B) Unregulated commercial fishing.

C) Their lower reproductive ability.

D) Contamination of sea water.

55. How does global warming affect the survival of turtles?

A) It threatens the sandy beaches on which they lay eggs.

B) The changing climate makes it difficult for their eggs to hatch.

C) The rising sea levels make it harder for their hatchlings to grow.

D) It takes them longer to adapt to the high beach temperature.

56. The last sentence of the passage is meant to _________.

A) persuade human beings to show more affection for turtles

B) stress that even the most ugly species should be protected

C) call for effective measures to ensure sea turtles' survival

D) warn our descendants about the extinction of species

Passage Two

Questions 57 to 61 are based on the following passage.

There are few more sobering online activities than entering data into college-tuition calculators and gasping as the Web spits back a six-figure sum. But economists say families about to go into debt to fund four years of partying, as well as studying, can console themselves with the knowledge that college is an investment that, unlike many bank stocks, should yield huge dividends.

A 2008 study by two Harvard economists notes that the "labor-market premium to skill" - or the amount college graduates earned that's greater than what high-school graduate earned - decreased for much of the 20th century, but has come back with a vengeance (報(bào)復(fù)性地) since the 1980s. In 2005, the typical full-time year-round U.S. worker with a four-year college degree earned $50,900, 62% more than the $31,500 earned by a worker with only a high-school diploma.

There's no question that going to college is a smart economic choice. But a look at the strange variations in tuition reveals that the choice about which college to attend doesn't come down merely to dollars and cents. Does going to Columbia University (tuition, room and board $49,260 in 2007-08) yield a 40% greater return than attending the University of Colorado at Boulder as an out-of-state student ($35,542)? Probably not. Does being an out-of-state student at the University of Colorado at Boulder yield twice the amount of income as being an in-state student ($17,380) there? Not likely.

No, in this consumerist age, most buyers aren't evaluating college as an investment, but rather as a consumer product - like a car or clothes or a house. And with such purchases, price is only one of many crucial factors to consider.

As with automobiles, consumers in today's college marketplace have vast choices, and people search for the one that gives them the most comfort and satisfaction in line with their budgets. This accounts for the willingness of people to pay more for different types of experiences (such as attending a private liberal-arts college or going to an out-of-state public school that has a great marine-biology program). And just as two auto purchasers might spend an equal amount of money on very different cars, college students (or, more accurately, their parents) often show a willingness to pay essentially the same price for vastly different products. So which is it? Is college an investment product like a stock or a consumer product like a car? In keeping with the automotive world's hottest consumer trend, maybe it's best to characterize it as a hybrid (混合動(dòng)力汽車); an expensive consumer product that, over time, will pay rich dividends.