In Asia the prequake behavior. of animals【C1】______successfully to warn people that earthq

uakes【C2】______. Recently, a group of American【C3】______and geophysicists visited India and listened【C4】______great interest【C5】______the scientists there【C6】______explained how they have been able to predict many earthquakes in the past three years. The Indian scientists use【C7】______, but, they also【C8】______strange signals such as various ground noises, the fluctuation of well-water levels, and the strange behavior. of animals. The results are quite【C9】______. Indian seismologists(地震学家), for example,【C10】______predicted two magnitude 6. 9 quakes. The seismologists【C11】______that their predictions have been【C12】______precise that they were able to evacuate(疏散)many of their people【C13】______an earthquake occurred, thus【C14】______thousands of lives. On the other hand, the Indian experts also admit that there have been some false alarms. American scientists【C15】______stories of【C16】______prequake animal behavior. before, but they【C17】______them too seriously until their recent visit to Asia. "Maybe theres【C18】______to it," said Jack Everndon, a California scientist. "We need some kind of short-term warning. We need something. " He didnt mention the kind of research he may be considering. "Some of us are thinking its【C19】______enough to give it a serious look," he commented, "two years ago we【C20】______that. "

【C1】

A．have used

B．have been used

C．has been used

D．will be used