题目

大气中氮氧化物和碳氢化合物受紫外线作用可产生二次污染物一光化学烟雾，其中部分物质的反应过程如图所示。下列说法正确的是（） A . 该过程中O2作催化剂 B . 反应过程中没有电子转移 C . 反应过程中氮氧化物不断被消耗 D . 丙烯转化为甲醛和乙醛 答案：D假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加，删除或修改。增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。删除：把多余的词用斜线（\）划掉。修改：在错的词下划一横线，并在该词下面写出修改后的词。注意：1．每处错误及其修改均仅限一词； 2．只允许修改10处，多者（从第11处起）不计分。Keeping a diary in English is the effective way to improve our English writing ability．First, it takes little time to finish a diary than other writings．By keeping English diaries, we can easy form the habit of thinking about in English．Second, we can practice use English idioms and useful structures in our diary-writing．If we have difficulty finding suitable words or phrases to express our opinion, we can turn in English dictionaries or teacher for help．This is also a kind of learning．If we can keep on doing this, we would gradually learn how express ourselves in English freely．In a word, it was of great benefit to keep diaries in English．