Passage 13（2019 •江苏省南京市）
 
Though times have changed, falling asleep in class is still a common occurrence (常事) among teenagers.
Why do students sometimes fall asleep in class? An obvious reason is lack of sleep. However, there are also causes for getting too little sleep. However, there are also causes for getting too little sleep. Homework is a daily occurrence for most students, one that can take three to four hours per night. A teenager who wants to be able to take part in any activity besides homework must stay up late to fit everything in. Club activities, sports, computer-game playing, and TV viewing, for example, all contribute to (促成) teens having less time for both homework and sleep. Sometimes teens lack sleep because of after-school jobs that are taken on to earn extra money for college, family expenses, or simply for clothes.
Physical problems are another factor that can cause students to fall asleep in class. For example, insomnia, which may keep a student up at night, causing exhaustion (疲惫不堪) during class hours, is a serious problem that may require medical attention. Medical evidence also supports the idea that each person has a body clock that helps to decide his or her sleep pattern. Unluckily, these body clocks do not always work according to school timetables.
The effects of falling asleep in class can be quite serious. First of all, sleeping in class is not a good way to endear (使受喜爱) yourself to teachers. In addition, it is highly possible that other students may make jokes about those who sleep in class. However, the most harmful effects of sleeping in class is missing out on important points. In the long run, sleepers may end up failing classes.
Since teens are probably not going to deal with the problem, falling asleep in class will probably remain an all-too-common occurrence. It will continue until more teens find a way to balance their personal and social lives with school and work, while still finding enough time to sleep.

【答案与解析】
【文章大意】文章介绍了上课睡觉的原因，可能是因为睡眠不足，课下有作业和一些要参加的活动，不可能有充足的睡眠，还有一个原因就是失眠，有的孩子的生物钟和上课时间不一致，这需要药物的帮助，上课睡觉不仅让老师不喜欢，听课也以失败而告终。上课睡觉仍然是一个常见的事情，直到青少年找到一个平衡他们自己和社会工作的方法，有了足够的时间睡觉。
42．but  【解析】根据Though times have changed, falling asleep in class is still a common occurrence (常事) among teenagers.可知是但是上课睡觉想当普通；故填but。
43．finish  【解析】根据Homework is a daily occurrence for most students, one that can take three to four hours per night.可知是为了完成作业；故填finish。
44．balance  【解析】根据A teenager who wants to be able to take part in any activity besides homework must stay up late to fit everything in.可知是为平衡有活动的作业；故填balance。
45．enough  【解析】Sometimes teens lack sleep because of after-school jobs可知是没有足够的时间睡觉；故填enough。
46．stop/prevent  【解析】根据insomnia, which may keep a student up at night可知是失眠阻止学生晚上睡觉，stop/prevent sb doing sth阻止某人做某事；故填stop/prevent。
47．match  【解析】根据Unluckily, these body clocks do not always work according to school timetables.可知是学生的生物钟和学校的时间表不匹配；故填match。
48．liked/loved  【解析】根据sleeping in class is not a good way to endear (使受喜爱) yourself to teachers.可知上课睡觉不被老师喜欢，被动语态be+过去分词；故填liked/loved  。
49．risk/possibility  【解析】根据In addition, it is highly possible that other students may make jokes about those who sleep in class.可知上课睡觉的学生有被嘲笑的风险或可能性；故填risk/possibility。
50．fail  【解析】根据In the long run, sleepers may end up failing classes.可知在学习上不及格；故填fail。
51．solved  【解析】根据Since teens are probably not going to deal with the problem, falling asleep in class will probably remain an all-too-common occurrence. It will continue until more teens find a way to balance their personal and social lives with school and work, while still finding enough time to sleep.可知直到青少年能掌控他们的生活，处理学习和工作，有足够的时间睡觉，问题才能解决，根据句子结构可知用被动语态；故填solved。