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.

老师例5，7的平方49，没有超过100啊，为什么不能选？

老师，这道题你换了好几次思路，真的没听懂！谢谢！

老师这道题没懂，我也不会拆分！

老师这个是怎么解出来的？拆分？这么大的数不会拆哦

老师，这里不懂条件1怎么算出来的， 40怎么来的？谢谢！

PS：|nx-8|≤4，有多少个整数n使得恰好只有2个整数解x？ 求问may老师

老师，这里看不懂二分之Q减一是什么？

老师例7的A怎么能成立呢？把2带进去，一个方程俩未知数啊？

讨论的71那三个情况不是3的倍数？70那俩是三的倍数？213能被三整除啊，其他不能整除怎么70那些都是3的倍数呢？谢谢哦！

我觉得这道题应该选E，因为当ab同时大于1，原命题成立，当ab同时大于0小于1，原命题不成立