* Sentences can have any number of prepositional phrases: There's no limit to how many prepositional phrases a sentence can contain. You could have a sentence with zero, one, two, three, or even more prepositional phrases.
* Example with more than two: "The cat sat on the mat in the living room under the window." This sentence has three prepositional phrases.
What matters is grammatical correctness: The number of prepositional phrases is less important than how they are used and whether the sentence makes sense grammatically.
Key takeaway: While a sentence *can* have two prepositional phrases, it's not a rule or limitation.