根据句意及首字母提示写出所缺单词。
1. Only two rulers are red, the r_____ are yellow.
2. I'm worried about the s_____ of the children because they've never been there before.
3. Don't b_____ your father now. He's working.
4. You'd better wear a shirt and a t_____ .
5. When you are in t_____, you can turn to me for help.
1. rest 2. safety 3. bother 4. tie 5. trouble