a small run-down factory的用法和样例：
- The steamer ran down a small fishing boat.
- A small stream ran down among the rocks.
- The cyclist was run down by a lorry.
- It's a lovely sunny day; why don't we run down to the coast?
- That was a close thing! I was nearly run down by the car.
- I'll lay on a car tomorrow and have you run down to Shanghai.