根据句意及首字母提示填空。
1. You may call the police when you are in t____.
2. Beijing is in the n____ of China.
3. The headmaster called on (号召) the students to r____ money for the poor boy.
4. In China, when you see the yellow lights, please s____ down.
5. I want to book a s____ room with two single beds.
