1. They are my grandparents. 他们是我的祖父母。

2. They are playing basketball. 他们正在打篮球。

3. They are studying in the library. 他们正在图书馆学习。

4. They are waiting outside the gate. 他们正在门外等待。

5. They are singing a song. 他们正在唱歌。

6. They are watching a movie. 他们正在看电影。

7. They are traveling to Japan. 他们正在去日本的路上。

8. They are learning new skills. 他们正在学习新技能。

9. They are helping with the garden. 他们正在帮忙园艺。

10. They are enjoying their vacation. 他们正在享受假期。

希望这些句子对你有所帮助!如果有更多关于特定主题或情境的需求，请告诉我。