做原子吸收光谱分析时,哪种火焰的温度最高()
A.煤气-空气
B.氢气-氧气
C.乙炔-空气
D.乙炔-氧化亚氮
E.丙烷-氧气
参考答案:D
解析:乙炔-氧化亚氮火焰的温度最高
— I hear Johnson was badly injured in the accident.
— ________, let's go and see him. [ ]
A. If not
B. If so
C. If necessary
D. If possible
六一儿童节有42个小朋友到森林公园划船,一共租了10只船.每只大船坐5人,每只小船坐3人.租用大船有______只,小船有______只.