填空题
《复合题被拆开情况》 Speed Skating is a winter racing sport where athletes compete against one another on an ice-based circuit, using skates to navigate their way around the track. There are three main【C1】________ ( vary) of speed skating—Long Track Speed Skating, Short Track Speed Skating, and Marathon Speed Skating. In the Olympics, "Speed Skating" is the term used to describe the Long Track category,【C2】whe________ Short Track Speed Skating is abbreviated to "Short Track". Speed Skating was developed at some point during the 19th Century, and whilst its precise origins are routinely debated, the first【C3】________ (compete) events can be traced back to Norway in 1863. It has been a part of the Winter Olympics from the very beginning,【C4】________four separate men’s events held in 1924. Since 1960, a number of women’s events have been introduced, as well as Team Pursuit events in recent years.