The weight of a body ______ with latitude and altitude, its mass does not. (variable)

《雷公炮炙论》

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《炮炙大法》

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《本草蒙筌》

A uniform substance doesn’t cope well with knocks because only a small proportion of the material is actually (8) . All the energy from the blow goes towards breaking the material in one or two places, but often the pieces left (9) are pristine (未经破坏的).

But instead of the energy being concentrated in one place, the holes provide many weak spots that all absorb energy as they break, says Vincent. "You are controlling the places (10) the wood breaks, and it can then absorb more (11) , more safely. "

The researchers believe the principle could be applied to any material- (12) example, to manufacture lighter and more protective packaging. It could (13) be used in car bumpers, crash barriers and arm our for military vehicles, says Ulrike Wegst, (14) the Max Plank Institute for Mental Research in Stuttgart. But she emphasizes that you (15) to design the substance with the direction of force in mind. "The direction of loading is crucial," she says.

Then, mark the corresponding letter on the Answer Sheet. When I was walking down the street the other day, I happened to (61) a small brown leather purse lying on the sidewalk. I (62) it up and opened it to see if I could (63) the owner’s name. There was nothing inside it (64) some change and an old photo—a picture of a woman and a young girl of about twelve years old, who looked (65) the woman’s daughter. I put the photo back and (66) the purse to the police station, where I (67) it to the desk sergeant. (68) I left, the sergeant took down my name and address (69) the owner might want to write and thank me. That evening I went to have dinner with my aunt and uncle. They (70) a young woman (71) there would be four people (72) the table. Her face was familiar. I was (73) sure that we had not met before, but I could not remember where I had seen her. In the course of conversation, (74) , the young woman happened to mention that she had lost her purse that afternoon. (75) I realized where I had seen her. She was the young girl in the photo, although she was now (76) . She was very surprised, of course, (77) I was able to describe her purse to her. Then I explained that I had (78) her from the photo I had found in the purse. My uncle (79) to the police station immediately to claim the purse. As the police sergeant handed it over, he said that it was an (80) coincidence that I had not only found the purse, but also the person who had lost it.

Another (2) that she was late for a Monday class because she was recovering from drinking too much at a wild weekend party.At colleges and universities in the US, e-mail has made professors more approachable (平易近人). But many say it has made them too accessible, (3) boundaries that traditionally kept students at a healthy distance.

These days, professors say, students seem to view them as available (4) the clock, sending a steady stream of informal e-mails.

"The tone that they take in e-mails is pretty astounding (令人吃惊的) ," said Michael Kessler, an assistant dean at Georgetown University. "They’ll (5) you to help: ’I need to know this. ’"

"There’s a fine (6) between meeting their needs and at the same time maintaining a level of legitimacy (正统性) as an (7) who is in charge. "

Christopher Dede, a professor at the Harvard Graduate School of Education, said (8) show that students no longer defer to (听众) their professors, perhaps because they realize that professors’ (9) could rapidly become outdated.

"The deference was driven by the (10) that professors were all-knowing sources of deep knowledge," Dede said, and that notion has (11) .

For junior faculty members, e-mails bring new tension into their work, some say, as they struggle with how to (12) . Their job prospects, they realize, may rest in part on student evaluations of their accessibility.

College students say e-mail makes (13) easier to ask questions and helps them learn.

But they seem unaware that what they write in e-mails could have negative effects (14) them, said Alexandra Lahav, an associate professor of Law at the University of Connecticut.

She recalled an e-mail message from a student saying that he planned to miss class so he could play with his son. Professor Lahav did not respond.

"Such e-mails can have consequences," she said. "Students don’t understand that (15) they say in e-mail can make them seem unprofessional, and could result in a bad recommendation. \

When Spanish football club Barcelona paid US $35 million for Ronaldinho last summer, they weren’t buying a pretty face. "I am (1) ," admits the Brazilian superstar (超级明星). "But everyone has got a different kind of beauty. What I (2) have is charm. "

Indeed he has. His buck teeth (龅牙), flowing hair, big smile, and of course his (3) skills are always eye-catching on the pitch. The 23-year-old striker (中锋) scored two goals in a 3-2 win over Deportivo La Coruna on March 1. It was Barcelona’s sixth win in a row and, thanks to their Brazilian’s 10-goal contribution, (4) looked like a poor season could now end a success.

Ronaldinho-full name Ronaldo De Assis Moreira-is one of many South Americans who learned their skills playing in the backstreets before (5) them off on the world stage.

Great things were (6) when Gremio signed him as a seven-year-old, and he soon became friends with Ronaldo, who was then the other young star of Brazilian football. It was Ronaldo who first called him Ronaldinho, which (7) Little Ronaldo.

He first (8) for his country in 1999 but it was at the 2002 World Cup where he showed his real worth, scoring an unbelievable free-kick in Brazil’s quarter-final victory (9) England.

"I have never failed to deliver in big matches," Ronaldinho says. "My game is based on improvisation (即兴表演). Often a forward does not have the time to decide whether to shoot or (10) . It is instinct that gives out the orders. "

While he may not have David Beckham’s good looks, Ronaldinho has a (11) reputation off the pitch. At former club Paris Saint Germain, which sold him to Barcelona, he broke (12) rules by going out and enjoying the city’s nightlife. "Without doubt, Ronaldinho is the most (13) player I have ever come across," says former PSG coach Luis Ferdandez. "The main (14) for any coach is that one player without discipline can hurt the whole team. "

But Ronaldinho doesn’t think he has done anything wrong. "I am just a young person who enjoys (15) ," he says.