根据规定，进行明火作业的技术条件之一是空气中含氧量达到（）%以上。
A.1
B.5
C.8
D.19.5
参考答案：D
Charlie is going to have problems finding a job ________ he gets his A levels.[ ]
A. even if
B. now that
C. as though
D. so that
伤及表皮的是（）。
A.Ⅰ°烧伤
B.浅Ⅱ°烧伤
C.深Ⅱ°烧伤
D.Ⅲ°烧伤
E.轻度烧伤
