关于动车组的试运行是如何规定的？

Walk along the River Warnow, in northern Germany, and you may be lucky enough to spot a SeaFalcon, a sleek, white machine with two propellers, two wings and a distinctly unbirdlike tail. It looks like an aircraft. Which is what it is. Except, it isn’t. It is a ship—at least in the eyes of the International Marine Organisation, which regulates such things. That matters, because ships are much more lightly regulated than aircraft.
The SeaFalcon is really a ground-effect vehicle. It flies only over water and only two metres above that water. This means the air beneath its wings is compressed, giving it additional lift. In effect, it is floating on a cushion of air. That makes it far cheaper to run than a plane of equivalent size, while the fact that it is flying means it is far faster—at 80-100 knots—than a ship of any size. Its designer, Dieter Puls, thus hopes it will fill a niche for the rapid transport of people and light goods in parts of the world where land and sea exist in similar proportions.
The theory of ground-effect vehicles goes back to the 1920s, when Carl Wieselsberger, a German physicist, described how the ground effect works. There was then a period of silence, followed by a false start. In the 1960s the Soviet armed forces thought that ground-effect vehicles would be ideal for shifting heavy kit around places like the Black Sea. Their prototypes did fly, but were never deployed in earnest and their jet engines consumed huge amounts of fuel.
This did, however, prove that the idea worked. And two German engineers, Mr. Puls and Hanno Fischer (whose version is called Airfish 8), have taken it up and made it work by using modern, composite materials for the airframes, and propellers rather than jets for propulsion. One reason the Soviet design was so thirsty is that the power needed to lift a ground-effect vehicle is far greater than that needed to sustain it in level flight. The Soviet design used heavy jet engines to deliver the power needed for take-off. But the SeaFalcon uses a hydrofoil to lift itself out of the water, and Airfish 8 uses what Mr. Fischer calls a hoverwing—a system of pipes that takes air which has passed through the propeller and blasts it out under the craft during take-off.
The next stage, of course, is to begin production in earnest—and that seems to be about to happen. Mr. Puls says he has signed a deal with an Indonesian firm for an initial order of ten, while both he and Mr. Fischer are in discussions with Wigetworks, a Singaporean company, with a view to starting production next year. South-East Asia, with its plethora of islands and high rate of economic growth is just the sort of place where ground-effect vehicles should do well.
All of which sounds optimistic. But a note of caution is needed. For another sort of ground-effect vehicle was also expected to do well and ended up going nowhere. The hovercraft differed from the vehicles designed by Messrs Puls and Fischer in that it relied on creating its own cushion of air, rather than having one provided naturally. That meant it could go on land as well as sea—which was thought at the time (the 1950s) to be a winning combination. Sadly, it was not. Hovercraft have almost disappeared. But then, in the eyes of the regulators, they counted as aircraft.

2010秋季开学以来，关于各地高中语文教材“大换血”的讨论甚是热闹，因其中涉及的鲁迅作品较多，被称为“鲁迅大撤退”。对于鲁迅的“撤退”，外界观点可谓针锋相对。支持者认为新时期作家的作品更具当下价值，反对者则担心青少年在上语文课时缺失人文理想。这种争论反映了[ ]

①任何事物均具有两面性

②不同认识主体对同一客体的反映必然会有所不同

③对同一事物不同人的意识具有主观选择性

④不同认识的对立源于立场的根本不同

A、①②

B、②③

C、③④

D、①③

简述正文的起草应注意的问题。

要学好自然科学，需认真观察、积极思考并动手实验．下列是一位同学在学习和生活中遇到的问题，请你帮助

学习了电路的串、并联知识后，赵明问：“家中的电视机、电灯、电风扇等电器之间是以什么方式连接？”“当然是并联”小玲回答说．哪些现象能说明它们是并联的？______．

现代社会出现了古代社会所没有的工程、机电、航空之类的专业学校，这说明制约学制建立的因素是( )。

A．社会意识形态

B．社会政治经济制度

C．本国文化历史传统

D．生产力发展水平