Directions: Fill in each blank with a proper word chosen from the box. Each word can only be used once. Note that there is one word more than you need.

A. accounts       B. determine       C. sites            D. halves               AB. handy       AC. processing AD. simply       BC. statues        BD. pouring       CD. confusing       ABC. case

Egyptian Pyramids

Researchers have uncovered one of the key methods the Egyptians used to build the pyramids. They have long been confused by exactly how workers were able to transport large blocks of stone of construction【小题1】. Now, they say the key was simple-wet sand.

“For the construction of the Pyramids,the ancient Egyptians had to transport heavy stone blocks and large【小题2】across the desert.” researchers at the University of Amsterdam said. The team tried to repeat this—and found wet sand was the key. The Egyptians therefore placed the heavy objects on a sledge(雪橇) that workers pulled over the sand.

Research from the University of Amsterdam has now revealed that the Egyptians probably made the desert sand in front of the sledge wet. Experiments have demonstrated that the correct amount of wetness in the sand【小题3】the pulling force required. To test the theory. the physicists placed a laboratory version of the Egyptian sledge in a tray of sand. They decided both the required pulling force and the stiffness(硬度) of the sand as a function of the quantity of water in the sand. To【小题4】the stiffness, they used a rheometer, which shows how much force is needed to deform a certain volume of sand. Experiments revealed that the required pulling force decreased proportional to the firmness of the sand. “In the presence of the correct quantity of water. wet desert sand is about twice as firm as dry sand.” the team said. A sledge glides far more easily over firm desert sand【小题5】because the sand does not pile up in front of the sledge as it does in the【小题6】of dry sand. They also believe a painting reveals the trick. “The Egyptians were probably aware of this【小题7】trick.” they said. “A wall painting in the tomb of Djehutihotep clearly shows a person standing on the front of the pulled sledge and【小题8】water over the sand just in front of it.”

The research results could therefore be useful for examining how to make full use of the transport and【小题9】of grand material,which at present【小题10】for about ten percent of the worldwide energy consumption.