走黄的表现 A． * * 口常有精液溢出 B．排尿困难、尿潴留 C．阴囊肿大偏坠，但无红热

第一个问题是有关比较标的的，即转基因食品和非转基因食品之间进行比较时，真正进行比较的是什么。现行的比较仅仅是衡量食品中一些主要和次要的营养物质、已知毒素和其他一些破坏营养物质的成分等的含量。但是，目前并没有一个标准的清单列出需要衡量的物质和不需要衡量的物质。此外，也没有一个程序来追踪检测难以预料且不希望出现的变化。 下列有关“比较标的”的表述，不正确的一项是( )。

A．“比较标的”是指转基因食品和非转基因食品之间的比较内容

B．现行的比较仅仅是比较转基因食品和非转基因食品中的一些主要和次要的营养物质

C．目前还没有一个标准的清单列出需要衡量的物质和不需要衡量的物质

D．用“实质等同”这个标准来比较转基因食品和非转基因食品，并不可靠

The importance of agriculture cannot be overstated. More than 50 percent of the world’’s labor force is employed in agriculture. The distribution in the early 1980s ranged from 67 percent of those employed in Africa to less than 5 percent in North America. In Western Europe, the figure was about 16 percent; in Eastern Europe and the Soviet Union, about 32 percent; and in Asia, about 68 percent.Farm size varies widely from region to region. Recently the average for Canadian farms was about 186 ha (about 460 acres) per farm, and for U.S. farms, about 175 ha (about 432 acres). The average size of a single landholding in the Philippines, however, may be somewhat less than 3.6 ha (less than 9 acres), and in Indonesia, a little less than 1.2 ha (less than 3 acres).Size also depends on the purpose of the farm. Commercial farming, or production for cash, is usually done on large holdings. The plantations of Latin America are large, privately owned estates worked by tenant labor. Single-crop plantations produce tea, rubber, cocoa. Wheat farms are most efficient when they comprise some thousands of hectares and can be worked by teams of people and machines. Australian sheep stations and other livestock farms must be large to provide grazing for thousands of animals.Individual subsistence farms or small-family mixed-farm operations are decreasing in number in developed countries but are still numerous in the developing countries of Africa and Asia. A "back-to-the-land" movement in the U.S. reversed the decline of small farms in New England and Alaska in the decade from 1970 to 1980.The conditions that determine what will be raised in an area include climate, water supply, and terrain.Over the 10,000 years since agriculture began to be developed, peoples everywhere have discovered the food value of wild plants and animals and domesticated and bred them. The most important are cereals such as wheat, rice, barley, corn and rye.Agricultural income is also derived from non-food crops such as rubber, fiber plants, tobacco, and oilseeds used in synthetic chemical compounds. Money is also derived from raising animals for pelt.Much of the foreign exchange earned by a country may be derived from a single commodity; for example, Sri Lanka depends on tea, Denmark specializes in dairy products, Australia in wool, and New Zealand and Argentina in meat products. In the U.S., wheat has become a major foreign exchange commodity in recent years.The importance of an individual country as an exporter of agricultural products depends on many variables. Among them is the possibility that the country is too little developed industrially to produce manufactured goods in sufficient quantity or technical sophistication. Such agricultural exporters include Ghana with cocoa, and Myanmar with rice. On the other hand, an exceptionally well-developed country may produce surpluses not needed by its own population; this has been true of the U.S., Canada, and some of the West European countries.

由下丘脑合成的激素是（）

A．催产素

B．醛固酮

C．促肾上腺皮质激素

D．促甲状腺激素

创伤性连枷胸是指（）

A.双肋骨骨折

B.多根肋骨骨折

C.多处肋骨骨折

D.两侧胸部多根肋骨骨折

E.多根多处肋骨骨折

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