1. my sister / visit / ho chi minh city / next sunday . 2. we / have / small party / the weekend . 3. they / going / swimming / this afternoon ? 4. john / going / rock climbing / his classmates / next...

Here are the correct sentences: 1. My sister is going to visit Ho Chi Minh City next Sunday. 2. We are going to have a small party this weekend. 3. Are they going swimming this afternoon? 4. John is going rock climbing with his classmates next Saturday. 5. My brother is going to use my bike this evening. 6. Jenny and Mary are going skating together tonight.