题目

根据短文内容及首字母提示，填写所缺单词。 Do you know how to make friends with a group of people? Let me t____1____ you the steps about making friends with the group. Maybe it’s h___2____ to you. First, you need to know what k___3___ of group they belong to. If people of the group are shy(害羞的), never ask them “Why don’t you talk?” or “Why are you quiet?” They don’t like it, so d____4___ do it. N____5___, remember that each group is different. They will use different words, find different things funny . Then, the important thing is that you should tr 已知(1)H2(g)＋O2(g)H2O(g)；ΔH1＝akJ/mol (2)2H2(g)＋O2(g)2H2O(g)；ΔH2＝bkJ/mol (3)H2(g)＋O2(g)H2O(1)；ΔH3＝ckJ/mol (4)2H2(g)＋O2(g)2H2O(1)；ΔH4＝d kJ/mol 下列关系式中正确的是 [　　] A． 2a＝d＜0 B． b＞d＞0 C． 2a＝b＜0 D． 2c＝d＞0