题目

根据以下3个热化学方程式：2H2S(g)+3O2(g)＝2SO2(g)+2H2O(l) △H＝Q1 kJ/mol 2H2S(g)+O2(g)＝2S (s)+2H2O(l) △H＝Q2 kJ/mol 2H2S(g)+O2(g)＝2S (s)+2H2O(g) △H＝Q3 kJ/mol 判断Q1、Q2、Q3三者关系正确的是（） A . Q1>Q2>Q3 B . Q3>Q2>Q1 C . Q1>Q3>Q2 D . Q2>Q1>Q3 答案：B It’s known to everyone that trees are important to us．The most important is that they can ________ oxygen for us． [　　] A． protect B． produce C． prevent D． take in