无忧无虑

例句：

1. 1. She was so happy that she felt completely free from worry.
   她非常开心，感觉完全没有忧虑。
2. 2. The children were care-free and enjoyed their summer vacation.
   孩子们无忧无虑，享受着他们的暑假。
3. 3. He is care-free because he doesn't have to worry about anything.
   他无忧无虑，因为他不用担心任何事情。