有人认为：“过去五千年的中华通史，实为一部‘帝王专制史’；而现代的中华通史，则是一部‘民主政治史’”。从“过去”到“现代”的历史分界点应该是下列选项中的
A．鸦片战争
B．辛亥革命
C．新文化运动
D．五四运动
答案：B
题目分析：本题考查的是中国古代和近代的政治制度。“帝王专制史”是指从公元前221年秦朝建立到1912年清朝末代皇帝退位这一时期的专制主义中央集权制度，“民主政治史”是指辛亥革命推翻了2000多年的封建专制统治，，建立了中华民国，实行民主共和政体，是中国历史的第一次巨变，B项正确。A、B、C都没有确立民主政治制度。
In this section you will find after each of the passages a number of questions or unfinished statements about the passage, each with 4 (A, B, C and D) choices to complete the statement. You must choose the one which you think fits best. The time for this section is 75 minutes.
| questions 1-5 are based on the following passage. Non-indigenous (non-native) species of plants and animals arrive by way of two general types of pathways. First, species having origins outside the United States may enter the country and become established either as free-living populations or under human cultivation-for example, in agriculture, horticulture, aquaculture, or as pets. Some cultivated species subsequently escape or are released and also become established as free-living populations. Second, species of either US or foreign origin and already within the United States may spread to new locales. Pathways of both types include intentional as well as unintentional species transfers. Rates of species movement driven by human transformations of natural environments as well as by human mobility-through commerce, tourism, and travel-greatly exceed natural rates by comparison. While geographic distributions of species naturally expand or contract over historical time intervals (tens to hundreds of years), species-ranges rarely expand thousands of miles or across physical barriers such as oceans or mountains. Habitat modification can create conditions favorable to the establishment of non-indigenous species. Soil disturbed in construction and agriculture is open for colonization by non-indigenous weeds, which in turn may provide habitats for the non-indigenous insects that evolved with them. Human-generated changes in fire frequency, grazing intensity, as well as soil stability and nutrient levels similarly facilitate the spread and establishment of non-indigenous plants. When human changes to natural environments span large geographical areas, they effectively create passages for species movement between previously isolated locales. The rapid spread of the Russian wheat aphid to fifteen states in just two years following its 1986 arrival has been attributed in part to the prevalence of alternative host plants that are available when wheat is not. Many of these are non- indigenous grasses recommended for planting on the forty million or more acres enrolled in the US Department of Agriculture Conservation Reserve Program. A number of factors perplex quantitative evaluation of the relative importance of various entry pathways. Time lags often occur between establishment of non-indigenous species and their detection, and tracing the pathway for a long-established species is difficult. Experts estimate that non-indigenous weeds are usually detected only after having been in the country for thirty years or having spread to at least ten thousand acres. In addition, federal port inspection, although a major source of information on non-indigenous species pathways, especially for agriculture pests, provides data only when such species enter via closely-examined routes. Finally, some comparisons between pathways defy quantitative analysis-for example, which is more "important": the entry path of one very harmful species or one by which many but less harmful species enter the country |
According to the passage, the US Department of Agriculture______.
A．is liable for the fast distribution of the Russian wheat pest
B．fails to isolate the Russian wheat aphid in limited locales
C．provides data about foreign species entering the country by regulated routes
D．is responsible for introducing harmful plants onto federal lands