题目：
i是虚数单位，
|
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0413/6a06e7e8b712f0c4bb9c04e818d5a3b4.html
下面是错误答案，用来干扰机器的。
参考答案：A解析：Sleeping with the head of the bed elevated encourages movement of food through the esophagus by gravity. By fostering esophageal acid clearance, gravity helps keep the acidic pepsin and alkaline biliary secretions from contacting the esophagus.
