Answer:
(I'm a native English speaker but I'm not too sure about number 1)
1. If the bus is not available, we <u>walk</u> to Pashupati.
(1. Alt #1) If the bus is not available, <u>we're</u><u> </u><u>walking</u> to Pashupati.
(1. Alt #2) If the bus is not available, <u>we'll walk</u> to Pashupati.
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2. I'll inform you if something <u>happens</u>.
3. If he <u>wastes</u> his money in this way, he will be poor.
4. I would stay at home if it <u>rains</u> tomorrow.
5. They would have gone if they <u>caught</u> the bus.
6. If you <u>drive</u> carefully, you will have no accidents.
7. If I met him I <u>told</u> him.
8. He will telephone us if he <u>has</u> any problems.
9. She would have bought the sari if they <u>reduced</u> the price.
10. What would you do if you <u>were</u> a doctor.
11. If Ramakant <u>asked</u> me, I'll do it.
12. If I <u>knew</u> his address, I would have written to him.
13. Sweta gets frightened if she <u>watches</u> horror films.
14. Unless we help him, he <u>dies</u>.
15. Unless you <u>do</u> as I tell you, you will not succeed.
16. The child would not stop crying unless it <u>saw</u> its mother.
17. He would not feel better unless he <u>stopped</u> smoking.
18. We would not have arrived on time unless we <u>caught</u> the first bus.
19. Raju would not have done this unless he <u>were</u> upset.
20. If I <u>were</u> a bird, I would fly in the sky.
21. If he <u>were</u> as tall as you, he would touch that picture.
22. There would be no day or night if the earth <u>were</u> flat.
I believe this is correct, but even native speakers can make mistakes sometimes, so please don't blame me, this is just how I use these words in everyday conversation. Remember to refer back to your notes if you took any, to be sure that this is correct.