用所给动词的适当形式填空。
1. We want to invite our classmates _________ (have) a picnic tomorrow.
2. —Millie, please tell your brother not to cross the road, it is dangerous.
—Thank you, I __________ (ask) him to be careful.
3. One of the red key rings__________ (belong) to Millie.
4. Why not __________ (visit) the Great Green Wall next month?
5. He is looking forward to __________ (spend) his holiday in Shanghai next month.
6. Can your sister __________ (sing) the song in English?
