Scientists are uncovering the secrets of two port cities lost under the waters of the Mediterranean Sea, a researcher said yesterday.
Herakleion and Menouthis were rich and proud cities until something reduced them to rubble (碎石) and buried them in the mud beneath 30 feet of sea water, French underwater explorer Franck Goddio said at the American Geophysical Union conference.
“This is a mystery that is ongoing,” said Goddio, a founder of the European Institute of Marine Archeology, a Paris-based underwater research organization backed by the wealthy Hilti Foundation of Liechtenstein(列支敦士登基金会).
The destruction of the twin port cities has haunted Goddio ever since he happened upon the site about 15 miles from Alexandria while exploring sunken ships from Napoleon’s fleet.
Goddio and his group of expert divers, marine archeologists(海洋考古学家) and others, are using high powered vacuums, satellite navigation systems and sophisticated sonar(声纳) to excavate(挖掘) the sunken cities from underneath a carpet of silt about one meter (three feet) high.
Walls of shops, remains of streets and gold artifacts have been found and recovered.
Some experts believe that the port cities were destroyed by a series of massive earthquakes, much like the quakes scientists believe felled Troy(特洛伊城), Jericho and other ancient cities. The uniform direction of the collapsed columns and walls suggest an earthquake, Goddio said, but no fault lines have been found nearby.
Other researchers believe a massive wave, caused by either an offshore earthquake or a distant underwater landslide, could explain the catastrophe. Still others think rising seas and a shift in the Nile River outlet doomed the cities.
“The argument, as you can see, continues,” Goddio said.
The reason why the two port cities disappeared under the waters of Mediterranean Sea is that ______.

A．the two port cities were destroyed by huge earthquakes

B．the disappearance of the two port cities was caused by underwater landslide

C．rising seas and a shift in the Nile River outlet doomed the cities

D．the story didn’t tell us at all

From the story we can draw a conclusion that _______.

A．the two port cities were famous for their wealth and the mystery

B．the two cities belonged to France

C．some mysterious creatures from other planets destroyed the two cities

D．the American Geophysical Union conference was once held in one of the two cities

This article is probably from _______.

A．a scientific magazine

B．a report to the government

C．a school text book

D．a scientific report in a newspaper