词形变换：根据句意，写出所给单词的适当形式。

1. My classmates are from six ________ (country).

2. Danny and Jenny often go for a ________ (walk) after supper every day.

3. An airplane is ________ (fast) than a bus.

4. Laughing ________ (loud) is good for your health.

5. I can see some girls __________ (play) on the square.

6. "Where ________ (be) you yesterday?" "I was in the library."

7. Look! Jenny is ________ (look) out of the window of the train.

8. The ________ (child) are packing their suitcases. They are going to Beijing.

9. My father ________ (go) to the factory from Monday to Friday.

10. Danny ________ (break) his tail at the Palace Museum last week.