根据句子意思，用括号中所给单词的适当形式填空，并将答案填写在答卷纸标号为46-50的相应位置上。
The story happened about two        (century) ago.
Besides the funny actors in the film, the story         (it) is really interesting.
In China, the number “eight” is thought to be a          (luck) number by many people.
We can make a big difference to the earth by         (do) small changes.
The elephant is seriously ill. It is       (die).