根据汉语提示,用词组的适当形式填空。
1. A key is ______ (用来) opening and locking a door.
2. There are some ______ (少先队员) in the picture.
3. We must ______ (向……学习) each other and help each other.
4. Mr. Mott was in the meeting room ______ (刚才).
5. Today Mum is going to cook ______ (一些美味的东西) for us.