请高手帮我分析此句的英语句型和成分

请高手帮我分析此句的英语句型和成分Well,by the time the last joke had been told,every one of the twelve was sitting perfectly still,desperately holding in the laughter which was bursting to get out.此句主句应该是 "every one of the twelve was sitting perfectly still" 而"by the time the last joke had been told"应作时间状语从句"desperately holding in the laughter which was bursting to get out"应该是分词短语做方式状语修饰sit吧..当然"which was bursting to get out"是定语从句修饰laughter...