1.Because knowledge is acquired or personal gain of information and Understanding is the perception of this acquisition.According to writer ,When we get knowledge when it is realized by our emotions then it become an understanding.
2.According to writer ,understanding can not passed because it is a personal/subjective phenomenon.And understanding is an abstraction wheres as knowledge implies concepts and symbols during its acquisition.
3.Yes ,it is possible .when understanding is expressed in terms of symbols.
4. Understanding is feelings ,emotions of people which are experienced only .whereas understanding /or feelings and personal actualization of symbols is knowledge of understanding.
5.I endorse writer`s point of view .Because knowledge is acquired and understanding is the outcome of personal feelings and experiences.