单选题 Cyclo-cross is a cross-country bicycle racing in open and usually quite rough country with riders often forced to dismount and carry their bicycles. The sport, originated early in the 20th century in France, was prevalent in the 1920s, but became prominent in the 1950s (the British Cyclo-Cross Association was founded in 1954). An original European sport, cyclo-cross became popular throughout Western Europe and in the United States. World championships were initiated in 1925; by 1950 these were recognized by the Union Cyclist International(International Cyclists' Union). After 1967 amateur and professional classes were officially separated in competition. The 24-kilometer cyclo-cross course, often involving taps, is usually completed in 60 minutes. A course typically includes obstacles such as ditches, mud, fallen trees, streams, flight of stairs, fences, and gates; artificial hurdles are added to insufficiently challenging natural courses. Cyclo-cross races are usually held from September to March, adding winter weather hazards to the challenge . There is a massed start with the field assembling not more than two abreast. Helpers are often stationed around the course with spare bicycles in case the original machine encounters mechanical difficulties or becomes too weighted down by mud picked up to the course.

单选题 What does the word "dismount" in Paragraph * One mean?

单选题 According ro the passage, which of the following is NOT true about cyclo-cross?

【正确答案】 C

【答案解析】解析：细节题。A项可以在第一段中得到，选手有时会扛着自行车；B项在第四段第一行可以得到，选手被安排成两两发车；D项在第四段第二句，会有助手准备了备用自行车在旁边等着；只有C项说所有的选手都同时在起跑线出发，与原文不符。

单选题 Cyclo-cross became widely known______.

单选题 According to the passage, cyclo-cross races are usually held from September to March because______.

【正确答案】 B

【答案解析】解析：细节题。第三段最后一句讲自行车越野赛在9月至次年3月举行。冬天恶劣的气候使比赛更具挑战性(Cyclo—cross races are usuany held from September to March，adding winter weather hazards to the challenge)，hazard表示“危险”的意思。