题目

下列化学符号中的数字“2”表示的意义不正确的是 （  ） A．2Na:“2”表示两个钠原子     B．NO2:“2表示两个氧原子 C．2OH- :“2”表示两个氢氧根离子    D．:“ +2表示氧化镁中镁元素的化合价为+2价 答案：B 阅读理解 　　The clock struck(敲)eleven at night．The whole house was quiet．Everyone was in bed except me．Under the strong light, I looked sadly at a huge pile(堆)of those trouble things-books． 　　I was going to have my exam the next day．“When can I go to bed?” I asked myself．I didn't answer．And I could not．The clock struck twelve．“Oh, dear! Ten more books to read before I go to bed!” We students are the most wretched ones in the world．Dad does not agree with me on this．He did not have to work so hard when he was a boy． 　　The clock struck one．I was quite hopeless now．I forgot all I did learn．I was too tired to go on．I did the only thing I could．I prayed(祈祷), “My god, please let me pass the exam tomorrow．I will work hard next time, Amen．” My eyes were so heavy that I could hardly open them．A few minutes later, with my head on the books, I fell asleep． (1) The word “wretched” in Line 6 means ________． [　　] A． very happy B． forgetful C． unlucky D． hopeful (2) What do you think happened to the writer? [　　] A． He was late for the exam． B． He passed the exam luckily． C． He failed in the exam． D． He fell asleep during the exam． (3) The best title for the passage is ________． [　　] A． The Night Before The Exam B． Working Far Into Night C． A Slow Student D． Going Over Lessons