a can of coffee的用法和样例：
- He went into the Terrace and asked for a can of coffee.
- It's the same buying a can of coffee or a quart of milk.
- Please give me a can of "Edgeworth".
- He opened a can of beer and drank it.
- To open, pull tab, eg on a can of beer.
- While fishing, he usually opens a can of worms.