根据句意、首字母和汉语意思完成单词。

1. When you a______ in Beijing, please call me.

2. Your mother is w______ for you at the school gate.

3. When you visit someone, please k______ at the door.

4. I often help my mother w______ the dishes.

5. —Why are you late today? —B______ I get up late.

1头大象的重量等于8头牛的重量，一头牛的重量等于2匹马的重量。一匹马的体重是300千克，一头大象的体重是多少千克？