a speck of dirt的用法和样例：
- I've got a speck of dirt on my shirt.
- I've got a foreign body(eg an insect or a speck of dirt)in my eye.
- Instead of making him feel like a speck of dirt, be his friend.
- I've got a foreign body (eg an insect or a speck of dirt) in my eye.
- If you get a speck of dirt in your eye, wash it out with a special eyewash.
- She polishes the machine every day so that there's not a speck of dirt on it.