单项选择题

Nowadays groups of scientific workers, often supposed by their governments, spend their time studying the occurrence of earthquakes. It is very likely that they will be able to (47) earthquakes or influence the direction of their movements, which are determined by events far below the surface of the earth. But the facts they report and the theories suggested by those facts may enable scientists to (48) the centers of future earthquakes and even predict the time of their occurrence. It is only when the (49) of events that we call an earthquake can be seen as a pattern that predictions can be made. Part of its pattern is external and visible, or capable of being recorded by sensitive instruments above the earth’’s surface. Scientists and engineers studied the shock waves of the San Francisco earthquake. Tile city was rebuilt and new features were (50) to strengthen buildings and (51) a constant water supply in the event of another earthquake. Large underground tanks were constructed to supply water if (52) supplies could not be tapped. Special (53) were taken to prevent fires, which often do more damage than earthquakes themselves. The San Francisco earthquake (54) scientists with valuable information. Since the effects of the break were visible at the surface, scientists could (55) what actually happened, and reports of the incident were an important (56) to the world’’s store of knowledge about earthquakes. WORD BANK A) prevent I) warn B) formal J) normal C) locate K) measures D) sequence L) introduced E) compensated M) consequence F) contribution N) observe G) provided O) recommended H) maintain