비자승인 메일이 왔는데요 무슨내용인지 알려주세요~

EMPLOYER WORK LIMITATION - 8547

The holder must not be employed by any 1 employer for more than 6 months, without the prior permission in writing of the Secretary.

STUDY LIMITATION - 8548

While in Australia you must not engage, for more than 4 months, in any studies or training.비자를 받았는데요 이런내용이 있는데 무슨뜻이예요??

비자승인 예제랑 좀 다르네요. 알려주세요~