气体烧嘴有几种？哪几种？
参考答案：
有三种。
（1）有焰烧嘴
（2）无焰烧嘴
（3）专供天然气燃烧的烧嘴
The workmen made so much___________ that Mrs. Walker had to spend three days cleaning
up afterwards. [ ]
A. trouble
B. damage
C. mess
D. nuisance
简述审证应包括的内容。
