以下关于人为水土流失因素的表述中,不确切的选项是()。A.陡坡开荒 B.过度放牧 C

题型:单项选择题

问题:

以下关于人为水土流失因素的表述中,不确切的选项是()。

A.陡坡开荒

B.过度放牧

C.项目建设活动

D.农业耕作活动

考点:水土保持防治工水土保持防治工题库
题型:单项选择题

豌豆花的顶生和腋生是一对相对性状,根据下表中的三组杂交实验结果,判断显性性状和纯合子分别为( )。

杂交组合 子代表现型及数量
甲(顶生)×乙(腋生) 101腋生,99顶生
甲(顶生)×丙(腋生) 198腋生,201顶生
甲(顶生)×丁(腋生) 全为腋生

A.顶生;甲、乙
B.腋生;甲、丁
C.顶生;丙、丁
D.腋生;甲、丙

题型:单项选择题

康士坦丁

题型:单项选择题

关于溶液的表面张力大小与产生泡沫多少的关系,下列说法正确的是()。

A.表面张力大,产生的泡沫多

B.表面张力大,产生的泡沫少

C.表面张力的大小和产生泡沫的多少无关

D.表面张力小,产生的泡沫多

题型:单项选择题

在SQL语句中,为了避免查询到重复记录,可用【 】短语。

题型:单项选择题

When an invention is made, the inventor has three possible (1) of action open to him: he can give the invention to the world by publishing it, keep the idea (2) , or patent it.

A (3) patent is the result of a bargain (4) between an inventor and the state, hut the inventor gets a limited period of monopoly and publishes full details of his invention to the public after that period (5) .

Only in the most exceptional circumstances (6) the lifespan of a patent (7) to alter this normal process of events.

The longest extension ever (8) was to Georges Valensi; his 1939 patent for color TV receiver circuit was extended until 1971 because for most of the patent’s normal life there was no color TV to (9) and thus no hope for reward for the invention.

Because a patent remains permanently (10) after it has terminated, the shelves of the library attached to the (11) office contain details of literally millions of ideas that are free for anyone to use and, if (12) than half a century, sometimes even repatent. Indeed, patent experts often advise anyone (13) to avoid the high cost of conducting a search through (14) patents that the one sure way of violation of any other inventor’s right is to plagiarize a dead patent. Likewise, because publication of an idea in any other form (15) invalidates further patents on that idea, it is traditionally (16) to take ideas from other areas of print. Much modern technological advance is (17) on these presumptions of legal security.

Anyone closely (8) in patents and inventions soon learns that most "new" ideas are, in fact, as old as the hills. It is theft reduction to commercial practice, either through necessity or dedication, or through the availability of new technology, (19) makes news and money. The basic patent for the theory for magnetic recording dates back to 1886. Many of the original ideas behind television originate (20) the late 19th and early 20th century. Even the Volkswagen rear engine ear was anticipated by a 1904 patent for a cart with the horse at the rear.

8()

A. granted

B. granting

C. to grant

D. being granted

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