佩戴红十字臂章的救护人员第一次在战场上出现，并提供人道服务，是在哪一年的哪次战争中？
参考答案：
1864年、日勒苏益格战役。
Language study is a process that you need to _____ something first and later on you can take something out. [ ]
A. put in
B. put down
C. put away
D. put through
