这道题正确答案是 B， 我一直觉得是D, 不是特别明白 B 答案为什么 说as effectively as sea snakes can? One such adaptation is the closer proximity of the terrestrial snake's heart to its head, which helps to ensure circulation to the brain, regardless of the snake's orientation in space. The heart of sea snakes can be located near the middle of the body, a position that minimizes the work entailed in circulating blood to both extremities. In arboreal snakes, however, which dwell in trees and often assume a vertical posture, the average distance from the heart to the head can be as little as 15 percent of overall body length. Such a location requires that blood circulated to the tail of the snake travel a greater distance back to the heart, a problem solved by another adaptation. 20. It can be inferred from the passage that which of the following is true of species of terrestrial snakes that often need to assume a vertical posture? (A) They are more likely to be susceptible to circulatory failure in vertical postures than are sea snakes. (B) Their hearts are less likely to be located at the midpoint of their bodies than is the case with sea snakes. (c) they cannot counteract the pooling of blood in lower regions of their bodies as effectively as sea snakes can. (d) the blood pressure at their midpoint decreases significantly when they are titled with their heads up.

请唐塘老师分析一下这道题，谢谢

想问下may老师什么时候变化率的计算公式 什么时候分母是被减数，什么时候是减数 像这题求时间的变化率分母是距离也就是被减数，但是对于其他年增长之类变化率的分母就是减数，想知道这个区别，谢谢老师

请文静老师解答：老师我读主旨大概总结为：各个政府开出优惠政策来吸引商家只会两败俱伤，这样不会创造更多的就业岗位，只会影响工作的布局。觉得B很核心的反应了文章主旨。因为从文章主旨上读出这样的行为各个政府都不受益只是影响工作布局罢了，那为什么政府还要重点关注E里竞争者开的条件呢？

老师您在讲课的时候把总数设为了a,将有副作用设为y,将有疗效设为了x,那通过条件（1）就可以知道有疗效为0.9a,没有疗效为0.1a,但是是怎么得出“没疗效有副作用”也为0.1a从而结合题设把y用a的式子表示的呢？感觉只能得出T这一栏里“没有疗效”的总数为0.1a哇

想问下may老师这题怎么做

想问下may老师怎么做

想问下may老师怎么做

[急] 这题七龙珠答案给的C，但是这里的contemporary只能是形容词或者名词，是不是不能直接接在名词后面用？如果这是个硬伤的话，E会不会更好一些呢？

[急] 请问May老师，这里通过连接下面圆的圆心，是不是是不是可以得到r跟b的直接关系，这样选A是不是就可以了呢？

当时老师讲的答案是A。statement 1 sufficient；statement 2 not sufficient。但是我现在不太理解了，觉得答案有些问题，能不能再详细的讲一下这道题怎么做？谢谢！