1. During National Holiday, I went out for a hiking in the near mountain with my friends.

2. October 1st was the 65th birthday of my motherland, China. My parents and I decided to go to the museum to review how our country was founded.

3. It's October 1 （the first）. It's National Day.

4. Today the country is celebrating the National Day.

5. National Day, the National Day, celebrating the country.

这些句子分别描述了不同人在国庆节期间的活动和感受，包括去远足、参观博物馆、挂红旗等。希望这些句子对你有所帮助。