- UID
- 639352
- 在线时间
- 小时
- 注册时间
- 2011-6-11
- 最后登录
- 1970-1-1
- 主题
- 帖子
- 性别
- 保密
|
On Pacific islands, a newly arrived gecko species, the house gecko, is displacing the previously established mourning gecko in urban areas, but populations of the two species are more stable in rural areas far from human settlement. The house gecko does not attack the mourning gecko, but in areas where insects congregate it prevents the mourning gecko from feeding on them.
Which of the following contributes most to an explanation of the difference between gecko populations in urban and rural areas?
(A) In urban areas, geckos are valued because they eat so many insects. (B) Geckos defend territories against other members of the same species. (C) House geckos that arrive on islands are carried there in boats and planes. (D) In places where there are lighted buildings, insects tend to gather around the light. (E) Mourning geckos are all females and reproduce asexually, but house geckos reproduce sexually.
答案是D,为什么不选B呢? Which of the following most logically completes the argument?
A new machine for harvesting corn will allow rows to be planted only fifteen inches apart, instead of the usual thirty inches. Corn planted this closely will produce lower yields per plant. Nevertheless, the new machine will allow corn growers to double their profits per acre because __________.
(A) with the closer spacing of the rows, the growing corn plants will quickly form a dense canopy of leaves, which will, by shading the ground, minimize the need for costly weed control and irrigation (B) with the closer spacing of the rows, corn plants will be forced to grow taller because of increased competition for sunlight from neighboring corn plants (C) with the larger number of plants growing per acre, more fertilizer will be required (D) with the spacing between rows cut by half, the number of plants grown per acre will almost double (E) with the closer spacing of the rows, the acreage on which corn is planted will be utilized much more intensively than it was before, requiring more frequent fallow years in which corn fields are left unplanted 答案是A,为什么不选D呢?像这种句子没说完的题,怎么做啊?思路应该是怎样的呢? Traveler: Southern Airways has a far worse safety record than Air Dacentaria over the past few years, in terms of both the frequency of accidents and the severity of accidents. Therefore, although Air Dacentaria is slightly more expensive, I will choose it over Southern Airways for my flight from Pederton to Dacenta, since it is worth paying extra to have a safer flight.
Which of the following, if true, casts the most serious doubt on the traveler's argument?
(A) Air Dacentaria's flight from Pederton to Dacenta is nonstop, whereas Southern Airways' flight touches down in Gorinda on the way. (B) Most Southern Airways flights, but not its flight from Pederton to Dacenta, use Sarmouth airport, which because of its mountainous location is one of the world's most dangerous. (C) For its flights from Pederton to Dacenta, Southern Airways uses a different model of airplane, with a smaller capacity, than the model Air Dacentaria uses for its flights on the same route. (D) Only in the last few years has the cost of flying from Pederton to Dacenta been more expensive on Air Dacentaria than on Southern Airways. (E) Although the frequency of accidents is greater on Southern Airways, on both airlines the proportion of flights that have accidents is very small. 答案是B,为什么不选D呢。。。 To improve the long-term savings rate of the citizens of Levaska, the country's legislature decided to implement a plan that allows investors to save up to $1,000 per year in special accounts without paying taxes on the interest earned unless withdrawals are made before the investor reaches age sixty-five. Withdrawals from these accounts prior to age sixty-five would result in the investor's having to pay taxes on all the accumulated interest at the time of withdrawal. Which of the following, if true, most strongly supports the prediction that the legislature's plan will have its intended effect? A. The money saved in the tax-free savings accounts will be deposited primarily in those banks and financial institutions that supported the legislation instituting the plan. B. The majority of people choosing to take advantage of the tax-free savings accounts will withdraw their money prior to age sixty-five. C. A significant number of the citizens of Levaska will invest in the tax-free savings accounts well before they reach the age of sixty-five. D. During the ten years prior to implementation of the plan, Levaskans deposited an increasingly smaller percentage of their annual income in long-term savings accounts. E. People who are not citizens of Levaska are not eligible to invest in the tax-free savings accounts, even if their income is taxable in Levaska.
答案是C,我没想明白。我选的是D。 希望大家解答一下,非常感谢~ |
|