英语语法问题不懂啊

The manager was worried about the press conference his assistant was giving in his place,but luckily,everthing was going on well .括号里是was going ,能加be动词was吗?为什么,看这个句子I am worried about the meeting held in Guangzhou 这个句子怎么没有was held 不懂啊?
答：关键是你还不会句子分析：
1.这是一个并列复合句：前一并列分句(+定语从句）+but+ 后一并列分句
前一并列分句=The manager was worried about the press conference 经理为这个记者发布会而担心.
定语从句：（that) his assistant ( was giving ) in his place.-->还原：his assistant was giving the press conference in his place.他的助手正在代他发布这个记者招待会.
后一并列分句= luckily,everthing was going on well ,所幸,一切顺利.
2.I am worried about the meeting held in Guangzhou.
分析：主句：I am worried about the meeting.
held in Guangzhou 过去分词作后置定语,相当于定语从句=which is held in Guanzhou