If it was "a bat eats a bee" it would include the word "mot". But because it doesn't, it would be "the bat eats the bee". Also, I think if the sentence includes the classifiers (in this case "con") then it automatically means it's "the". I might be wrong about that last bit though.
Why is "ong" pronounced like "am"? That's what it sound like to me at least.
The "ng" sound is swallowed. The mouth closes at the end, which makes it sound a bit like an "m" sound.
Some vowels(such as U and O) will make the final -ng/-k labialized, a labialized -ng sounds like -m+-ng (simultaneously), and a labialized -k sounds like -p+-k (simultaneously also)