Составить 5 предложений, из слов must и mustn't буду

1.when was the radio invented? 2.the book was written by pushkin. или: was the book written by pushkin?

i saw an elephant for the first time in a zoo, when i was 4. this animal is very big, elephants live in india. people there use the elephants for transportation of trees and other heavy things. i like this animal because it is clever. i wish everyone could see this amazing animal, one must go and see it.