Question

read aloud record toolkit question powered by body heat. 2 body heat might sound like an unlikely source of power, but it has several advantages compared to oil and other traditional sources of energy: it is free, renewable, and available everywhere. furthermore, traditional energy sources will someday be depleted. so even people with access to electricity hope to exploit alternative sources - such as these three other unusual possibilities. what is the meaning of the word alternative as it is used in paragraph 2? different from normal challenging to use impossible to find simple to manufacture read paragraph 2. highlight the detail that tells you the meaning of alternative.

Explanation:

在文中，“alternative”所在句子提到“与石油和其他传统能源相比”，后文又说“其他不寻常的可能性”，可推测“alternative”有“与常规不同”之意。“different from normal”符合语境。“challenging to use”（使用有挑战）、“impossible to find”（不可能找到）、“simple to manufacture”（制造简单）均不符合上下文对“alternative”的表意。

Answer:

第一个选项“different from normal”。