单选题35. In the country of Seligia where asbestos has been used extensively in construction, that use is about to be banned, because the exposure of construction workers to asbestos can cause a certain type of cancer. We can predict that the ban will result in reducing the incidence of that type of cancer in Seligia by as much as 50 percent. It is true that less than 30 percent of the death certificates of Seligians who have died of that cancer have "construction" listed as the deceased's occupation. The cancer takes about 20 years after exposure to develop, however, and Seligians who have worked in construction commonly turn to less strenuous occupations as they age. Seligian death certificates indicate only the deceased's last occupation. In the argument given, the two highlighted portions play which of the following roles? ______

单选题In a certain box, there are 3 times as many red balls as blue balls. Which of the following is the ratio of the number of red balls to the number of blue balls?

单选题If the price of the clothes decreases from $25 to $20, what is the percent decrease in price?

单选题圆心在原点、半径为5的圆上有多少个整数点?

单选题 Some conservationists

单选题On a trip of 408 miles, Tom travels the first 160 miles in 4 hours. At what rate must he travel for the remainder of the trip in order to average 34 miles per hour for the entire trip? in miles per ho

单选题. ①Our study revealed that nest-guarding long-tailed skinks (a species of lizard) homed (returned to their nests) more successfully when displaced shorter distances. ②There are two reasons why homing success rates decreased with increasing displacement distance. ③One possibility is that females were simply displaced too far to find their way home. ④However, this is unlikely given that some individuals managed to find their way home from each distance we used. ⑤The second possibility deals with trade-offs between the risks associated with making a long return trip and the benefits of returning. ⑥Animals should expend energy only when the associated costs are low. ⑦As reptiles increase the time spent moving, their daily energy expenditure increases dramatically. ⑧The energetic costs of returning home and the chances that the eggs will have been preyed upon during the return trip both increase substantially as displacement distance increases. ⑨For example, the 130 hours (5.5 days) that female skinks spent returning from a distance of 300 meters is sufficient for an egg-eating snake to locate and prey upon the entire clutch. ⑩However, females with larger clutches were more likely to home at distances over 50 meters. For these females, the relative fitness benefits associated with having more eggs successfully hatch may outweigh the energetic costs of returning to a nest site, even if the nest may have already been preyed upon.25. The primary purpose of the passage is to ______

单选题 ①"Blues is for singing

单选题What is the smallest positive integer k for which 784 is a factor of 14k?

单选题Bob has 40 coins consisting only of dimes and quarters. If the number of dimes is 10 more than twice the number of quarters, what is the total value of the coins.

单选题 ①When selecting a nest

单选题. ①Exotic insect pests can produce both short-and long-term effects on forest ecosystems. ②Short-term effects include the disturbances directly associated with the action of the pest, which may cause the defoliation, loss of vigor, or death of trees. ③Long-term effects involve changes in tree species composition and the consequent alterations of forest structure, productivity, and nutrient uptake. ④Exotic pests are more efficient than most abiotic disturbances (e.g., fire or wind) at producing long-term changes in species composition. ⑤Pests often target specific tree species and, if they become established, they usually remain as permanent components of the ecosystem. ⑥Shifts in forest species composition ramify through the ecosystem in many ways because tree species have different, often unique properties.32. The passage mentions which of the following as effects of exotic pests on forest ecosystems? ______

单选题下面哪个方程在坐标系中表示的直线只通过一个横坐标和纵坐标都为整数的点?

单选题有7个数字：a，a，b，b，c，c，d，从中任取两个，问这两个数字相同的概率?

单选题. ①Early life insurers in the United States found themselves facing the problem of obtaining reliable information, as they needed to rely on applicants themselves to provide truthful, complete answers to a standard set of questions. ②In an attempt to personalize the relationship between insurers and their individual applicants, firms selected highly respected local citizens to act as their agents. ③These agents were expected to evaluate the appearance of candidates, unearth evidence of unhealthy family histories or questionable habits, and attest to the respectability of the people writing testimonial letters on an applicant's behalf. ④In short, the initial purpose of the agency system was not to actively solicit customers, but, rather, to recreate the glass-bowl mentality associated with small towns or city neighborhoods.3. The primary purpose of the passage is to ______

单选题有1，2，3，4，5五个数，如果偶数不能够相邻，问能够构成多少个5位数?

单选题The median of x, 15, 10 and y is 18.5. If x＜y, what’s the value of x?

单选题If two liters of a solution that is 15 percent salt will be added to 5 liters of a solution that is 8 percent salt, what percent salt will the resulting solution contain?