题干

国家标准规定以A0、A1、A2、B1、B2等标记来表示纸张幅面规格,以“克重”来表示纸张每平方米的质量.刘刚家新买回一包打印纸,包上标注着“A4 70 g 500 sheet 210×297mm”,意思是该包纸是500张规格为70g、210mm×297mm的A4通用纸.刘刚想知道这种纸的厚度和密度,只需用刻度尺测出这报纸的厚度.如果刘刚测得这包纸的厚度为5cm,那么这种纸的厚度是____ mm,密度是____ kg/m3

上一题 下一题 0.0难度 选择题 更新时间:2013-04-24 03:09:09

答案(点此获取答案解析)

0.1,700

同类题2

阅读理解

    Have you ever run into a careless cell phone user on the street? Perhaps they were busy talking, texting or checking updates on WeChat without looking at what was going on around them. As the number of this new “species” of human has kept rising, they have been given a new name —phubbers(低头族).

    Recently, a cartoon created by students from China Central Academy of Fine Arts put this group of people under the spotlight. In the short film, phubbers with various social identities bury themselves in their phones. A doctor plays with his cell phone while letting his patient die, a pretty woman takes selfie in front of a car accident site, and a father loses his child without knowing about it while using his mobile phone. A chain of similar events eventually leads to the destruction of the world.

    Although the ending sounds overstated, the damage phubbing can bring is real.

    Your health is the first to bear the effect and result of it. “Constantly bending your head to check your cell phone could damage your neck,” Guangming Dailyquoted doctors as saying, “the neck is like a rope that breaks after long-term stretching.” Also, staring at cell phones for long periods of time will damage your eyesight gradually, according to the report.

    But that's not all. Being a phubber could also damage your social skills and drive you away from your friends and family. At reunions with family or friends, many people tend to stick to their cell phones while others are chatting happily with each other and this creates a strange atmosphere, Beijing Evening News reported.

    It can also cost you your life. There have been lots of reports on phubbers who fell to their death, suffered accidents, and were robbed of their cell phones in broad daylight.