题目

A、B、C、D、E是初中化学常见的物质，A是大理石的主要成分，E是气体单质，A与B的反应用于实验室制取二氧化碳，它们的相互关系如图所示(图中“﹣”表示两端的物质间能发生化学反应，“→”表示物质间存在转化关系；部分反应物、生成物或反应条件已略去)： 请回答： (1)E的化学式是_______； (2)A和B反应的基本反应类型是________反应． (3)E→C反应的化学方程式为____________________． (4)物质D的一种用途是____________．Is there a difference in meaning between"It's too late to telephone．Mary is asleep now．"and"It's too late to telephone．Mary will be asleep now．"9Yes．The difference is in the reason given for it being too late to telephone．In the first sentence"Mary is asleep now"，the speaker is stating（陈述）a fact．In the second sentence"Mary will be asleep now"，the speaker is saying what Mary usually does．In fact，it's possible that Mary isn't asleep，but she is usually asleep at this time．So let's take two situations．In the first case，imagine Mary's mother answers the telephone．You："May I speak to Mary，please？"Mother："No．It's too late．Mary is asleep now．"You："Are you sure？It's only 10 0'clock．"Mother："Yes．I went to her room and she was asleep．"The mother knows that Mary is asleep because she went into her room and saw her．Here is another case．Two friends decide to telephone Mary．Jack："Let's telephone Mary．It's 10 0'clock．"Jill："No．It's too late．She will be asleep now．"Jill knows that Mary always goes to bed before 10o'clock，so now she'll probably be asleep．But it is also possible that she is staying up late．【1】In the first situation．Mary's mother___．A. is afraid to wake up MaryB. wants to tell you that she knows Mary is asleepC. knows that Mary wants to sleep at this timeD. wants to know if she can take a message for Mary【2】In the second situation，Jill___．A. knows that Mary has gone to bedB. doesn't know whether Mary is asleepC. is sure that Mary cannot answer the telephoneD. thinks it's possible that Mary cannot answer the telephone【3】In which situation do you think the word"will"is used in the same way Jill uses it？___A. Will you please lend me a hand？B. It's too heavy，I think．I'll help you．C. Don't get into his office．He will be angry now．D. You won't have to come to my office．I will send it to you．