ambiguity - Is the following sentence ambiguous?

Bob bought Anna's house.

Does this mean Bob bought a house from Anna, or Bob bought Anna's house for her, or both?

Answer

 Bob bought Anna's house.

The sentence doesn't reveal whether Anna's possession of the house occurred before or after the purchase you mention, so both is possible.

Either Bob bought the house and gave it to Anna,
Or Bob bought the house that up until then belonged to Anna.