a cardboard box的用法和样例：
- We keep our rice in a cardboard box.
- Building a bed out of a cardboard box.
- She brought the shopping home in a cardboard box.
- Mrs Ramsay was instructed to place the money in a cardboard box and to leave it outside her door.
- I saw a cardboard box with the head of a puppy sticking out.
- They marched solemnly into the house,carrying a cardboard box.