What are you doing tomorrow?

< She is playing water tomorrow






                    They are playing water (now) >





A. We use am/ is/ are + ing (present continuous) for something happening now:

• Where are Gladya and Cantika? 'They're playing water at a water park
• Please don't make a noise. We're having a test.

We also use am/ is/ are + -ing  for the near future (tomorrow / next week  etc)

• Gladya is playing water tomorrow.

• I'm going to Betawi next week.

B. I am doing something tomorrow = I have arranged to do it / I have a plant to do it:

• Lisa is going to Jakarta on Saturday.
• We're having a birthday party next weekend.
• Are you meeting someone tomorrow night?
• Where are they going?
• Who are you meeting this evening?

C. Do not use the present simple (I study / do you teach  etc.) for plans & arrangements.

• I'm studying at home this evening.  (not  'I study')
• Are you teaching tomorrow morning?  (not  'Do you teach')
• Lucy isn't going home next week. (not  'Lucy doesn't go home')

But we use the present simple tense for timetables, programmes, trains, buses, planes  etc.:

• The train leaves at 7.00. 
• what time does the film begin?

Note:

present continuous - usually for people                   present simple - timetables, programmes  etc.

- I'm going to see a film tomorrow evening.            - The film starts at 7.30.
- What time are you leaving?                                    - What time does your bus leave?

See also:

- I'm going to do something