化学选择题在结构上一般由题干和选项两部分组成。题干由问句或陈述句构成，提供确定选项所需的前提条件和限定范围。选项即备选的答案，通常是提供几个正确和错误的结论，供判断和选择，如仅有一个选项是正确的，叫做单项选择题；若有两个以上选项是正确的，叫做多项选择... The chemistry multiple-choice questions are generally composed of two parts, the questions and options. The questions are made up of question or declarative sentences, providing the prerequisites and limitations needed to determine the options. The option is the alternative answer, usually to provide a few correct and wrong conclusions for judgment and choice, if only one option is correct, it is called single-choice question; if there are more than two options are correct, called multiple items select...