You may know about “junk food” like French fries.But do you know about “junk sleep”？

    Recently, a British survey found that electronic(电子的) products in teenagers' bedrooms are affecting(影响) their sleep.

    The survey was done among 1，000 British kids from 12 to 16.It found that 30% of them got just 4 to 7 hours of sleep every day.But doctors say they need 8 to 9 hours.

    Almost a quarter of the kids said they fell asleep more than once a week while watching TV, listening to music or using other electronic products.

    “This is very worrying，” said Dr.Chris Idzikowski，a British expert，“We call it 'junk sleep'．It means you don't get enough sleep and the quality of the sleep is bad, too.If you don't get a good rest，you don't perform well in school the next day.”

    The survey found that 40% of the kids felt tired each day，with girls between 13 and 16 feeling the worst.Nearly all the teenagers have a cellphone，an iPad or a TV in their bedrooms.And many of them have all the three.

如图所示，关于液体中a、b、c三点压强的说法正确的是（ρ_盐水=1.03×10³kg/m³）（　　）

Plan your time carefully and make sure you have some time ________ what you like every day.

材料  在1377年到1904年间获取进士的人中有42%来自下层社会。这种流动作为一种吸纳机制，增强了社会结构的弹性，并有利于对社会的驾取与整合。有学者把科举制度看作是古代联系社会动力和政治动力的纽带，是维护儒家学说正统地位的有效手段。

    科举制度的废除导致四民社会的解体与封建等级制的消亡，提高了农工商的地位。人们纷纷从“读书做官”的思想中解放出来，开始走向广阔的社会。1910年江苏省旧式士人从事实业者占比30.4%，新学堂毕业生与归国留学生从事实业者更是占比37%。一些士大夫开始办厂经商，如状元出身的孙家鑑、张春等在各地F击续投资办厂。科举制废除后各级各类学堂的大期実兴办，特别是女子教育的出现，扩大了教育对象。此外，新式课堂教学中逐步采用白话文取代文言文，而在教学内容上，传统的儒家经典只占27.1%，而数理化等新知识却占72.9%。这大大便利了近代新式教育的普及。

——杨齐福《科举制度的废除与近代社会的转型》