Question

英文数学 题目~ 帮个忙！ 跪谢 ORZ

题目： Studying group A,B,C and D four students are in a classroom. One is doing math questions. One is reading English. One is reading novel. One is writing letter. It's known that:
1) A is not reading English nor reading novel.
2) If A is not doing math, then D is not reading English
3) Its said that B is doing math, or reading English, but its not true.
4) If D is not doing math, then he is reading novel. But its also not true.
5) C is not reading novel, nor reading English.

Question: What are A,B,C, and D each doing?

要解释 为什么！！！！ 感谢了！ 会加分~

Answer 1

A is doing math questions.
B is reading novel.
C is writing letter.
D is reading English.
通过1）、3）、5）可知A不读英语和小说，B不写数学和读英语，C不读小说和英语，所以只能是D读英语。
通过1）、5）可知A不读小说，C也不读小说，而D读英语，所以只能是B读小说
通过2）可知A不做数学，D就不读英语，而现在D已经确定读英语，所以A做数学
最后剩下C写信

Answer 2

A应当是math，B novel C Letter D English
翻译如下：
4个学习小组干4件不同事：Math,novel,English,letter.
1)A不在读English也不在读Novel
2）如果A不在做Math，D不在读English
3）据说B在做Math或者读English，但这不对
4）如果D不在做Math，就在读novel。但也不对
5）C不在读novel也不在读English
分析，A和C都不可能是novel和english,所以这两个必须被分配到Math和Letter。假设A不在做Math，则根据2）D不在读English 又根据4）D不可能是Math也不可能是Novel，如果不在English，则是letter和A重复 所以A必然在Math，则C在letter
B不在Math不在English不在Letter所以是Novel
D就是English了

Answer 3

A doing math questions
B reading novel
C reading English
D writing letter

解释:由1345得
A math or letter
B novel or letter
C math or english
D english or letter
由2得,如果A不做math,则写letter,那么D也写letter,所以不成立,所以A写letter,接着一步步推理

Answer 4

A math
B novel
C leter
D English

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Answer 5

A is doing math .
B is reading novel .
C is writing letters .
D is reading English .