儿童卧室中常用的上下铺双人床，下铺床褥面到上铺床板底之间的空位高度不小于（）。A．8

小红在解一道四选一的选择题时，她只能判断选项A是错误的，于是就猜一个答案，则小红猜对的概率为______．

数据链路层采用了后退N帧(GBN)协议，发送方已经发送了编号为0～7的帧。当计时器超时时，若发送方只收到0、2、3号帧的确认，则发送方需要重发的帧数是( )。

A．2

B．3

C．4

D．5

如图所示，倾角θ=30°的光滑斜面上水平放置一条L=0.2m长的导线PQ，两端以很软的导线通入，I=5A的电流，方向由P流向Q．当竖直方向有一个B=0.6T的匀强磁场时，PQ恰能静止，求：

（1）导线PQ的重力的大小和该磁场的方向；

（2）若改变匀强磁场的大小和方向，使导线静止在斜面上，且对斜面的压力最小，求该磁场的大小和方向；

（3）若改变匀强磁场的大小和方向，使导线静止在斜面上，且磁感应强度最小，求该磁场的大小和方向．

Over lunch, a writer outlined a new book idea to his editor. It was to be a niche concern but promised much. The writer left the restaurant with a glow and decided to get an outline over soon. But days and weeks of being too busy turned to months and then, eventually, came the shocking discovery that his editor has been rather elusive of late for a reason: he has been busy crafting a book based on the writer’s idea, and it was now in the shops. An apocryphal tale, maybe, but it will send shivers down any writer’s spine. What’s more, if the writer were to turn to the law in such a dread scenario, the law would be of no use to him at all.
Phil Sherrell, a media lawyer with Eversheds, explains: "Intellectual property law protects the expression of ideas, not the ideas themselves." Sherrell agrees that "the distinction is not always satisfactory," but says that there needs to be a limit to the protection conferred on creativity by the law. "To extend the ambit of copyright protection to embrace ideas would be difficult in practice—how would the artist prove that they have conceived the idea if it has not been reduced to a tangible form It would also open the door to undesirably wide monopolies."
But copyright’s 300-year pedigree might be a cause for concern rather than veneration. The means by which we communicate has changed out of all recognition from the time when copyright was invented. Today, in the post-modernist world, what constitutes an artistic, literary or musical work is radically different, not least in the field of conceptual art. Here, copyright’s time-honoured reluctance to protect ideas is of dubious merit, according to Hubert Best, a media lawyer with Best ＆ Soames.
"If you look at Martin Creed’s [art installation] Work No. 227, The Lights Going On and Off, where is the work" asks Best. "Is it in the fact that a light bulb goes on and off, or in the concept I suspect it’s the latter. But old-fashioned copyright law does not cover this kind of thing." Creed’s Work No. 227 was an empty room in which the lights periodically switched on and off. It won the Turner Prize in 2001 to a predictable chorus of controversy. This goes with the territory in conceptual art, but other artists have found their work inspires not merely lively debate but accusations of plagiarism.
Last year, three weeks after he unveiled his diamond-encrusted, 50m skull, Damien Hirst was alleged to have stolen the idea for the work from another artist, John LeKay. In 2006, Robert Dixon, a graphics artist, said that Hirst’s print, Valium, was too close for comfort to one of his circular designs in The Penguin Dictionary of Curious and Interesting Geometry. Hirst had another brush with intellectual property law when Norman Emms complained about a 1m bronze torso which, he said was copied from a 14. 99 plastic anatomical toy. Emms later received a "goodwill payment" from the artist.
As one of the world’s wealthiest artists, Hirst is well-placed to fight such battles, but due allowance should be given for art’s intertextual essence. Writers borrow plots and embed allusions to their forebears, artists adapt well-known motifs, musicians play each other’s songs and sample existing riffs and melodies. But there is a fine line between plagiarism, and creative allusion, and it was considered by the courts in the case of Dan Brown’s The Da Vinci Code. The Court of Appeal upheld the initial ruling that Brown had not reproduced substantial content from The Holy Blood and the Holy Grail. The decision was also widely seen as confirming English law’s disinclination to protect ideas.
Yet if ideas can’t be protected, where does that leave the writer aggrieved by the appearance of his idea in another’s book "It sounds harsh," says Sherrell, "but unless a writer has gone some way to creating the work—by way of an outline and perhaps a chapter or two—there is no remedy if the same idea appears under another author’s name. However, given that everything is done on computers these days, it would be relatively easy to prove first creation by looking at the hard drive. Other than that, anyone in the creative arena should keep full and dated records to evidence their work. "
There is another thing that can be done. "You can impose a confidentiality obligation on those with whom you want to discuss your idea," says Best. "Non disclosure agreements (NDAs) are often used in the corporate world to give a contractual remedy for breach of confidence if an idea is stolen. But the trouble is that a writer, musician or artist who comes into a meeting wielding an NDA isn’t likely to make friends. It’s a fairly aggressive way to proceed." Best is doubtless correct when he says. "You’ve just got to get on with it and do it. Once your work exists, in material form, you can sue if anyone steals it.\

The passage introduced the artist Martin Creed’s Work No. 227 ______.

A．as it was most severely criticized by the media lawyer Hubert Best

B．because it displays the dubious nature of some contemporary works of art

C．because it won the Turner Prize in 2001 to a chores of controversy

D．as it was an example of conceptual art which causes accusations of plagiarism

采用碳素钢丝以先张法预制混凝土构件时，其最大张拉控制应力允许值为()。

A．0．70fptk

B．0．75fptk

C．0．80fptk

D．0．90fptk