根据句意和汉语提示，填写单词。

1. His brother is a _________(军人). He joined the army five years ago.

2. We must _________(面对) these problems and find ways to get over them.

3. The old man _________(将……视为) the poor boy as his own son.

4. ________ (除非) we work hard, we will hardly ever learn English well.

5. There is a popular saying in sports meeting, "________(友谊) first, competition second."