a jar of strawberry jam的用法和样例：
- I have bought a jar of strawberry jam.
- My family has a 10-pound slab hanging from a meat hook in its pantry, next to homemade sausage and jars of strawberry jam.
- How much is a jar of peanut butter?
- The recipe uses a jarful of jam.
- A jar of pickle will contain pickled cabbage.