燃烧炉系统主要包括：燃烧炉、（）、热风管路、柴油泵、油、气管路、阀门组架。
参考答案：换热器
I wonder if you’d mind ___________ a few questions.
A. we asking B. us asking C. our ask D. us to ask
绞合常数
. we asking B. us asking C. our ask D. us to ask