1,I shall never forget the school which I studied with my fellow-students ten years ago.
疑惑：
1） 本题里面的shall可以换为will 之类的吗?为什么?
2）本题是否可以吧which改为when?为什么?
答：1）shall可以改为will,现代英语,当主语为第一人称时,可以用shall,也可以用will,在疑问句中一般还是用Shall I...(但近来也看到过Will we...Will I...的用法）
2）不知道你怎么想的,School是时间吗?可将which改为where或前面加in.这里用which错,不是因为study是不及物动词,其实study是可以作及物动词的.不用它是因为,如果你将它看成及物动词,那就是说：
I studied the school with my fellow-students ten years ago.学习的是学校?研究的是这所学校?不合逻辑.只能理解成:In the school I studied with my fellow-students ten years ago.
in the school--> in which 或者where引导定语从句：
我将永远不会忘记那所我和我的同学在十年前就读的学校.
2,A carefully trained observer can discover details very easy although others never see them.
疑惑：
1）麻烦分析这个句子的语法结构,例如trained ,although 之类的.是什么用法?
2）这个题目改哪个地方好呢?
答：主句结构是Sb.can discover sth.very easily although others never see them.
carefully trained是过去分词短语作定语,修饰ovserver
although引导的是让步状语从句,如果不是一个错的话,应改为though较好.
2）将easy改成副词easily,although改为though
句意：一个受过严格训练的观察员能很容易地发现细节的问题,尽管其他人从来都看不出.
答：不用.