问题
填空题
根据句意，用括号内所给单词的适当形式填空。
1. I got the pen on my ________ (twelve) birthday.
2. Parents should teach their children to make decisions by ________ (they).
3. There are many little ________ (collect) in our class.
4. He was so tired that he fell fast _________ (sleep).
5. We must be careful when we _________ (across) the road.
答案
1. twelfth 2. themselves 3. collectors 4. asleep 5. cross
