【Anewresearchonstudents'sleepinghabitssaysthatmorethan70%ofstudentsdonotgetenoughsleep．Researchersfoundthatprimaryschoolstudentsget9hoursand10minutesofsleepanight，juniorhighschoolstudentsget8hoursand6minutes，】

　　A new research on students'sleeping habits says that more than 70% of students do not get enough sleep．

　　Researchers found that primary school students get 9hours and 10minutes of sleep a night，junior high school students get 8hours and 6minutes，and senior high school students get 7hours and 9minutes．None of those times are enough for each group．Not enough sleep can cause many kinds of problems in children and teenagers．

　　In 2007，Shanghai Municipal Education Commission （上海教育委员会） asked primary and middle schools in the city to adjust （调整） their schedulesso that students could get more sleep．Two years later，a research found that students at schools that adjusted their schedules got more sleep than in 2005．

　　The researchers hope that the government will take measures （措施） to make students have enough sleep．Students in other places may get even less sleep than those in Shanghai．

　　根据短文内容，选择正确的答案．

　　71．According to the passage，over___ of students do not get enough sleep．

　　A.50% B.70% C.90%

　　72．Students in junior high schools get___ of sleep a night．

　　A.9hours and l0minutes B.8hours and 6minutes C.7hours and 9minutes

　　73．The underlined word"schedules"can be best replaced by___．

　　A．timetables B．courses C．rules

　　74．The researchers hope that students can have enough___．

　　A．food B．books C．sleep

　　75．Which of the following is TRUE according to the passage？___

　　A．This passage is mainly about how to make students have enough sleep．

　　B．Schools in Shanghai were asked to adjust their schedules because their students gotless sleep than those in other cities．

　　C．Students in senior high schools sleep 57minutes less than those in junior high schools according to the new research．