题目内容：

D

The eruption of a volcano in the Canary Islands could trigger a “mega-tsunami”（巨大海啸）that would hit Atlantic coastlines with waves as high as 330 feet, scientists said on Wednesday. They said an eruption of the Cumbre Vieja volcano on La Palma, part of the Spanish island chain off West Africa, was likely to cause a massive chunk（大块）of rock to break off, crashing into the sea and kicking up huge walls of water higher than any other in recorded history. The tsunami would be capable of traveling huge distances at up to 500 miles an hour, the scientists said in a research paper to be published soon.

Simon Day, of the Benfield Greig Hazard Research Centre at the University College of London, said that as the volcano was not erupting at present, the short-term and medium-term risks were “negligible”. But Cumbre Vieja should be monitored closely for any signs of activity so that emergency services could plan an effective response, he said. “Eruptions of Cumbre Vieja occur at intervals of decades to a century or so and there may be a number of eruptions before its collapse（倒塌）,” said Day, who cooperated on the research with Steven Ward of the University of California. “Although the year-to-year probability of a collapse is therefore low, the resulting tsunami would be a major disaster with indirect effects around the world.”

The effects would spread north, west and south of the Canaries, with the west Sahara bearing the worst of the wave’s energy. The energy released by the collapse would be equal to the electricity consumption of the entire United States in half a year.

Immediately after the landslide（山崩）,a huge wave of water 93,000 feet high and tens of miles wide would form. As the landslide rocks moved deeper under water, a tsunami would develop. Within 10 minutes, the tsunami would have moved a distance of almost 155 miles. On the west Saharan shore, waves would probably reach heights of 330 feet.

Florida and the Caribbean, the final north Atlantic destinations to be affected by the tsunami, would have to brace themselves for 165-foot waves some eight to nine hours after the landslide. Wave heights toward Europe would be smaller, but substantial waves would hit the coasts of Britain, Spain Portugal and France. The research paper estimated water would penetrate several miles inland and that the devastation would cause trillions of dollars in damage.

76. What would be the result of a big chunk rock falling into the sea?

A. Waves would be very high.                                         B. The volcano would stop.

C. Walls of water would kick up a storm.                          D. An earthquake would take place.

77. The word “negligible”(Line 3, Paragraph 2) is closest in meaning to ______.

A. unimportant                    B. small                              C. predictable               D. avoidable

78. From the passage we may learn that the volcano erupts ______.

A. every year                                                                 B. every 5 to 9 years

C. every 10 to 100 years                                                        D. every 5 to 10 months

79. All of the following are true EXCEPT ______.

A future eruption of Cumbre Vieja volcano may experience a massive collapse

Waves generated by the landslide could even reach the coasts of the United States

The landslide-released energy is equal to half a year’s electricity consumption in the US

American scientists have managed to utilize the volcanic energy for civil purposes