50. (A) 154263 (B) 145362 (C) 142536 (D) 156234
(1) Many scientists are trying to predict earthquakes.
(2) Furthermore, the predicted earthquake may not take place at all.
(3) Instead, they are trying to design buildings and bridges that can resist earthquakes.
(4) Scientists cannot predict the exact location, time, or intensity of an earthquake.
(5) These predictions are, unfortunately, very uncertain.
(6) As a result, the scientists do not think it is useful to announce that an earthquake will take
place on certain day.