"he enjoys their praising her children at school. using passive voice, 为什么要加being？"

In this sentence, the phrase "their praising her children at school" is in active voice. To convert it into passive voice, the sentence should be rephrased as: "She enjoys her children being praised at school." In the passive voice construction, the subject (her children) becomes the object (her children) and the verb (praising) is changed to its passive form (being praised). The use of "being" is necessary to indicate the action happening to the subject (her children).

，咱们有七个游击队员，驻在这最前线上，守卫着边区。

《2019主持人大赛》表现抢眼的尹颂、张舒越、王嘉宁就先后登上央视春晚的舞台，在全国电视观众面前成功“刷脸”。， 有不少网友看好《新闻女王》能成为TVB的“救星”，但比起当年的大爆剧《使徒行者》，《新闻女王》似乎差了不是一星半点。

论坛上，各界代表踊跃发言，从不同角度提出加强全球产业链供应链合作的建议……首届链博会上，“链”上的活力随处可见。， 导语：三伏天吃饺子，一定要试试这个馅！清香可口，好吃不上火，比芹菜豆角好吃 “幸福就是厨房有烟火，院里有猫狗，朝暮有你我，一屋两人有她与我立黄昏，三餐四季有他问我粥可温”，人生在世要慢慢生活，好好吃饭，深深爱，不辜负！大家好，我是爱美食更爱生活的晓峰。