a covered wagon的用法和样例：
- They set off for the West in a covered wagon.
- An arch or hoop, such as one of those used to support the top of a covered wagon.
- It is legal to shoot an Indian on horseback, provided you are in a covered wagon.
- His business was a cover for drug dealing.
- She drew a cover over the typewriter.
- A covered place for walking, as in a cloister.