听力原文： Ice dancing developed from ballroom dancing, particularly the waltz, and was very popular in the early 1900s. It requires well-trained, exact footwork conformity with one another's steps and a keen sense of timing and rhythm. Ice dancing differs from pairs skating in that ice dancers are restricted to lifts no higher than the man's shoulders and there are no jumps. One skate must be on the ice at all times. Ice dancing competitions are made up of three principal parts as following. The first part to perform. is compulsories. Partners must perform. two dances selected by the ISU, for example, waltz, tango, or polka. It involves set patterns in which dancers perform. and repeat steps at certain points around the arena. Although the steps are predetermined, dancers are encouraged to interpret them for artistic charming. Each dance counts for 15 percent of a pair's final score. The original dance, formerly known as the original set pattern dance, requires skaters to design their own performance to their choice of music, set to a speed and rhythm previously announced by the ISU. It counts for 35 per cent of the final score, and skaters receive marks for composition and presentation. In the free dance, the partners perform. a dance to music of their choice. They are given marks for presentation and style. as well as for technical value. This dance counts for 50 percent of the final score. (30)