No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n’roll. Long-ago builders could have attached wooden poles to the stones and rolled them across the sand, the scientists say.
“Technically, I think what they’re proposing is possible,” physicist Daniel Bonn said.
People have long puzzled over how the Egyptians moved such huge rocks. And there’s no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.
The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect wokers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.
Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.
However , physicist Joseph West think there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , “Why don’t they just try rolling the things ? ” A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone “a lot easier to roll than a square”.
So he tried it.
He and his students tied some poles to each of four sides of a 30-kilogram stone block.That action turned the block into somewhat a wheel.Then they placed the block on the ground.
They wrapped one end of a rope around the block and pulled.The researchers found they could easily roll the block along different kinds of paths.They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.
West hasn’t tested his idea on larger blocks,but he thinks rolling has clear advantages over sliding.At least,workers wouldn’t have needed to carry cattle fat or water to smooth the paths.
It’s widely believed that the stone blocks were moved to the pyramid site by ______.

A．rolling them on roads

B．pushing them over the sand

C．dragging them on some poles

D．sliding them on smooth paths

What does the underlined word “it”in Paragraph 7 refer to?

A．rolling the blocks with fat.

B．Rolling the blocks on wooden wheels.

C．Rolling poles to move the blocks.

D．Rolling the blocks with poles attached.

Why is rolling better than sliding according to West ?

A．Because more force is needed for sliding.

B．Because less preparation on path is needed for rolling.

C．Because sliding on smooth road is more dangerous.

D．Because rolling work can be done by fewer cattle.

What is the text mainly about ?

A．An experiment on ways of moving blocks to the pyramid site.

B．An argument about different methods of moving blocks to the pyramid site.

C．An application of the method of moving blocks to the pyramid site.

D．An introduction to a possible new way of moving blocks to the pyramid site.