1. My sister is visiting Ho Chi Minh City next Sunday.

2. We are having a small party at the weekends.

3. Are they going swimming this afternoon?

4. John is going rock climbing with his classmates next Saturday.

5. My brother is using my bike this evening.

6. Jenny and Mary are going skating together tonight.

*GT: - HTTD: (+) S + am/is/are + V-ing

                     (?) Am/Is/Are + S + V-ing?

* I + am

  he/she/it/N số ít + is

  we/you/they/N số nhiều + are.