原子吸收光度法分析时，试样在火焰中经历哪四个阶段？
参考答案：
雾化、蒸发、熔化和解离、激发和电离。
Passengers are permitted ________only one piece of hand luggage onto the plane.[ ]
A. to carry
B. carrying
C. to be carried
D. being carried
碳笔
