1. It was very cold yesterday. 2. When did you meet him? 3. I haven't seen him since 2007. 4. How many mushrooms have you gathered? 5. Where did you put the newspaper? I want to read it, but cannot find it anywhere. 6. The new school began working last year. 7. At last I have done all my homework: now I shall go out. 8. The building of the house began early in April. 9. The rain has stopped but a cold wind is still blowing. 10. We have already solved the problem. 11. He came a moment ago. 12. I have never spoken to him.
Explanation: When talking about the reason or cause of being famous, use the preposition "for." For example, "famous for its customs" means that the tribe is well-known because of its customs.
2. The sad news came as a shock.
Explanation: When something is described as coming unexpectedly or being surprising, use the preposition "as." For example, "came as a shock" means that the sad news was unexpected and surprising.
3. She was tired after her long walk.
Explanation: When indicating the cause or reason for being tired, use the preposition "after." For example, "tired after her long walk" means that she became tired as a result of her long walk.
In summary, the correct prepositions in these sentences are:
-Hi, John!
-What are you watching on TV?
-I watch a film about aliens.
-Wow! Cool!
-Yeah!