76.我父亲小时候以卖报为生。(by)
77.我整天忙忙碌碌,现在已筋疲力尽。(on the go)
78.正在建设的那栋楼房将是一所学校。(定语从句、被动语态)
79.这么冷的天,我宁愿在家呆着也不愿出去散步。(would rather...than)
80.政府已经采取措施保护文物。(take measures)
参考答案：
76.When my father was a child,he made a living by selling newspapers.
77.I've been on the go the whole day and I'm worn out / tired out now.
78.The building which / that is being built now will be a school.
79.I would rather stay at home than go out for a walk on such a cold day.
80.The government has taken measures to protect cultural relics.
