a snake-oil salesman的用法和样例：
- An army, like a snake, fight on its belly.
- A snake was creeping along the wall.
- The panther held a snake in its jaws.
- She shuddered at the very thought of a snake.
- Once while performing at the Riviera Hotel in Las Vegas, he was presenting a "pitchman act," playing the role of a "snake oil" salesman from the wild west.
- I'm goosebumps all over when I see a snake.