这段英文的语法等问题

这段英文的语法等问题
David Lodge"Deaf Sentence"的一段.
讲的是一个退休的语言学教授.
请问：
miss这里讲的是他想念还是他失去了?
tasks这里讲的工作、任务,还是前面说的那么多“the structure of the academic week,the full diary of teaching.required report”等等?
最后一句"and ensured."这里修饰的是什么?是tasks还是he?谁（名词/代名词）ensured（保证）了?
He missed the calendar of the academic year which had given his life a shape for such a long time,its passage marked by reassuringly predictable events.He missed the rhythm of the academic year as a peasant might miss differences between the seasons if they were suddenly withdrawn; and he found he missed too the structure of the academic week,the full diary of teaching assignments,postgraduate supervisions,essay marking,committee meetings,interviews,and deadlines for this and that required report,tasks he used to grumble about but the completion of which gave a kind of low-level satisfaction,and ensured that one never,ever,had to confront the question:what shall I do with myself today?
您好，最后一个我不太明白。有人说修饰tasks。到底应该是哪个呢？