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题库 / Prep2012-CR-20
Public health official: Some researchers suspect that magnetic fields from high-voltage power lines can cause health problems for people who live especially near the lines. However, this is extremely unlikely: Beyond a distance of a few feet, the strength of the magnetic fields from high-voltage power lines is less than the average strength of magnetic fields in homes that are not located near such lines.
Which of the following would it be most useful to establish in order to evaluate the public health argument?
Whether magnetic fields in homes that are not located near high-voltage power lines can cause health problems for the residents of those homes
What proportion of people who live near high-voltage power fines believe that those fines may cause health problems
Whether high-voltage power lines are routed near residential in urban areas
What specific diseases or conditions are suspected by some researchers to result from exposure to magnetic fields from high-voltage power lines
What is the average strength of magnetic fields in workplaces that are not located near high-voltage power lines
类比题：此题类似于OG题目（原文：教室内in the classroom的儿童 use 电脑 → 导致手腕受伤；选项：控制control group -- 教室外outside the classroom的儿童）
Some researchers suspect that magnetic fields from high-voltage power lines can cause health problems for 【people who live especially near the lines ①近】.
However 然而, this is extremely unlikely: Beyond a distance of a few feet, the strength of the magnetic fields from high-voltage power lines is less than the average strength of magnetic fields in 【homes that are not located near such lines ②远】.
文章出现两个对照组：【people who live especially near the lines ①近】 v.s. 【homes that are not located near such lines ②远】
问题：找前提P
选项里Whether：回答Yes→有效；回答no→无效。
选项A：控制另一个对照组control group（√），限定条件（包括时间、地点……）--秒选
Whether magnetic fields in 【homes that are not located near high-voltage power lines ②远】can cause health problems for the residents of those homes
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