单项选择题

A．improve estimates of long-term earthquake probabiliti……

The early warning systems developed in the 1990's are used to

A．improve estimates of long-term earthquake probabilities.
B．tell people in the epicenter when the earthquake will come.
C．allow evacuation from the region that the earthquake will hit.
D．prepare people for earthquakes several minutes in advance.

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单项选择题After the Parkfield programme, experts concluded that earthquake prediction in terms of days and years was

A．chancy.
B．hopeful.
C．unrealistic.
D．difficult.

单项选择题The ambitious Parkfield programme was successful at least in one of the following aspects:

A．Scientists will be fully prepared with equipment to collect more information if an earthquake occurs.
B．It enabled scientists to predict an impending earthquake on time scales of hours to days.
C．A moderate earthquake did occur in the region sometime between 1985 and 1993 just as predicted.
D．People in the Parkfield region were less panic but more prepared for any coming earthquakes.

单项选择题Harlem was called the capital of Black America in the 1920s and '30s mainly because of its

A．art and culture.
B．immigrant population.
C．political enthusiasm.
D．distinctive architecture.

单项选择题At the beginning the author seems to indicate that Harlem

A．has remained unchanged all these years.
B．has undergone drastic changes.
C．has become the capital of Black America.
D．has remained a symbol of the dangers of inner-city life.

单项选择题Which of the following is NOT an appropriate depiction of the present-day Harlem

A．Harlem is now seen as a tourist attraction.
B．Harlem is becoming an expensive place to live in.
C．Harlem has transformed into a place of entertainment.
D．Harlem's crime rate remains the same as ever.