Here's a guide to filling in the sentences using the Present Simple, Present Continuous, Future Simple, and "be going to":

1. **will help** (help) as soon as I’m back home.
2. **will you show** (show) me your photo album?
3. **are spending** (spend) the weekend by the lake.
4. If the weather **is going to be** (be) good, we’ll have a barbecue in the garden.
5. What time **are we leaving** (leave)?
6. The train **leaves** (leave) in 10 minutes.
7. **is flying** (fly) your dad to NYC?
8. Look! They **are dancing** (dance). Let’s watch.
9. I promise I **will clean** (clean) my room after I come back home.
10. Do you think they **will believe** (believe) us?
11. Look! She **is crying** (cry).
12. We **are going** (go) to the opera house tonight.
13. The performance **starts** (start) at 6 p.m.
14. I hope they **will find** (find) a way.
15. What **will you do** (do)? Any ideas?
16. Perhaps someone **will probably win** (probably win) the main prize.
17. She **is going** (go) to Berlin by train tomorrow morning.
18. I’ve forgotten to tell her. I **am calling** (call) her now.
19. They will be disappointed if we **do not invite** (not invite) them to our party.
20. I guess the police **will follow** (follow) him.
21. What **will you do** (do) tomorrow afternoon?
22. Look! The men **are stealing** (steal) the car.
23. I suppose everything **will end** (end) well.
24. When **are you making** (make) the decision?

Feel free to adjust any verbs based on the context!