Word formation
For questions 1-8, read the text below. Use the word given in capitals at the end of some of the lines to form a word that fits in the gap in the same line.
基础词:
Ultramarathons, races longer than the standard marathon distance of 42 kilometres, have seen a huge 1. in numbers over the past twenty years. Some events take runners across deserts or over mountain ranges, and the 2. can last several days. For most people, the idea of running such distances seems 3., yet many participants are ordinary office workers with no 4. background. What attracts them? Many say it is the sense of 5. that comes from spending hours alone in the countryside. Others are drawn by the challenge of doing something they once thought was 6.. Doctors, however, warn that the sport is not without risks. Runners can suffer from 7. and dehydration, and injuries to knees and ankles are common. Proper training, which involves 8. increasing the distance you run each week, is essential.