问题 选择题

甲苯分子的二氯取代物的同分异构体共有

A.4种

B.6种

C.8种

D.10种

答案

答案:D

题目分析:若取代甲基上的2个H原子,有1种结构;

若取代甲基上1个H原子、苯环上1个H原子,则苯环上的Cl原子相对甲基有邻、间、对3种结构;

若全部取代苯环上的2个H原子,若其中1个Cl原子与甲基相邻,另一个Cl原子有如图所示四种取代位置,有4种结构;若其中1个Cl原子处于甲基间位,另一个Cl原子有如图所示2种取代位置,有2种结构;故甲苯的二氯代物共有1+3+4+2=10种,答案选D。

点评:该题是高考中的常见题型,属于中等难度的试题。试题综合性强,侧重对学生能力的培养,有助于培养学生的发散思维能力和创新思维能力。答题时注意苯环的二元取代利用“定一移一”书写,苯环三元取代采取“定二移一”书写原则。

解答题
阅读理解

My favorite English teacher could draw humor out of the driest material. It wasn’t forced on us either. He took Samuel Johnson’s dictionary, Addison’s essays, and many other literary wonders from the eighteenth century and made them hilarious, even at eight o’clock in the morning. The thing that amazed me most was that the first time I read these works on my own, some of them seemed dead, but the second time, after his explanation, I couldn’t believe that I hadn’t seen the humor. The stories and poems and plays were suddenly filled with allusions(典故) and irony and hilarious moments. I learned more from him than from any other teacher.

My least favorite English teacher also made people laugh. Some students found him to be wonderfully funny. Many others did not. He assigned journals over a six-week period, to be written every day. At the end of the six weeks I had a notebook full of bits and pieces about my ideas, short stories, reactions to what we had read, and so on. Our teacher announced that we would be grading each other’s journals. Mine was passed to Joe, that class clown, who always behaved in a funny or silly way. He saw it fit to make a joke of and said, “This writing isn’t fit to line the bottom of a birdcage.” Our teacher laughed at that funny remark. It hurt me so much that the anger from it has driven my writing and teaching ever since.

So what makes the difference? Humor is one of the most powerful tools teachers or writers have. It can build up students and classes and make them excited about literature and writing, or it can tear them apart. It is true that humor is either productive or counter-productive and self-defeating.

小题1:The passage mainly discusses ________.

A.teaching

B.literature

C.humor

D.knowledge小题2:The underlined word “hilarious” in Paragraph 1 probably means ________.

A.funny

B.tiring

C.inspiring

D.brilliant小题3:The English teacher the writer disliked most ________.

A.was not able to make students laugh

B.hurt his student’s feelings

C.didn’t let his students do the grading

D.had no sense of humor