[填空题] At present groups of scientific workers, often 【26】 by their governments, spend their time in 【27】 the 【28】 of earthquakes. It is very 【29】 that they will be able to 【30】 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 【31】 by those facts may enable scientists to 【32】 the centers of future earthquakes and even 【33】 the time of their 【34】 . It is only when the 【35】 of events that we call an earthquake can be seen as a pattern that predictions can be made. Part of this pattern is external and 【36】 or capable of being recorded by 【37】 instruments above the earth’’ s surface. Scientists and engineers studied the 【38】 of the San Francisco earthquake. The city was rebuilt, and new features were 【39】 to strengthen buildings and maintain a 【40】 water supply in the event of another earthquake. The water mains ( = main pipes) were fitted with control valves which would ena
A. A．prevent
B．protect
C．warn
D．cause

[填空题] At present groups of scientific workers, often 【26】 by their governments, spend their time in 【27】 the 【28】 of earthquakes. It is very 【29】 that they will be able to 【30】 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 【31】 by those facts may enable scientists to 【32】 the centers of future earthquakes and even 【33】 the time of their 【34】 . It is only when the 【35】 of events that we call an earthquake can be seen as a pattern that predictions can be made. Part of this pattern is external and 【36】 or capable of being recorded by 【37】 instruments above the earth’’ s surface. Scientists and engineers studied the 【38】 of the San Francisco earthquake. The city was rebuilt, and new features were 【39】 to strengthen buildings and maintain a 【40】 water supply in the event of another earthquake. The water mains ( = main pipes) were fitted with control valves which would ena
A. A．provided
B．supplied
C．supplemented
D．supported