听力：What does the speaker say about kites？

No one knows for sure just how old kites are. In fact, they have been in use for centuries. 25 centuries ago, kites were well-known in China. These first kites were probably made of wood. They may even have been covered with silk, because silk was used a lot at that time.

Early kites were built for certain uses. In ancient China, they were used to carry ropes across rivers. Once across, the ropes were tied down and wooden bridges were hung from them. Legend tales of one general who flew musical kites over the enemy’s camp. The enemy fled, believing the sounds to be the warning voices of angels. By the 15th centuries, many people flew kites in Europe. Marco Polo may have brought the kite back from his visit to China. The kite has been linked to great names and events. For instance, Benjamin Franklin used the kite to prove that lightening is electricity. He flew the kite in a storm. He did this in order to draw lightening from the clouds. He tied a metal key and a strip of silk to the kite line. The silk ribbon would stop the lightening from passing through his body. Benjamin’s idea was first laughed at, but later on it led to the invention of the lightening rod.

With such grand history, kite flying is sure to remain an entertaining and popular sport.

Q: What does the speaker say about kites？

A.No one knows exactly where they were.

B.No one knows for sure when they came into being.

C.No one knows for what purpose they were.

D.No one knows what they will.