根据句子意思，用括号中所给词的正确形式填空。(每空填一词)
1. October 1 is the ________ (nation) Day of China.
2. Animals are human's friends, so protecting them is ________ (we) duty.
3. I think the chocolate with nuts is the ________ (nice) of all.
4. She's going to be a ________ (science) when she grows up.
