请教高手几个英语单句改错,告诉我应如何改正?原因?并翻译一下句子

请教高手几个英语单句改错,告诉我应如何改正?原因?并翻译一下句子
下列各句中,被【方括号】括住的地方就是错误之处,请改正,并用有关语法说明原因,最后翻译一下句子,谢谢
45 By the time the sun sets this evening,I will have finished the book 【I am writing】 for the last six years.
回答格式举例：
改正及原因：
翻译：
46 【While】 so many advances have been made in such a short time is the most valid argument fot retaining the research unit.
48. I could go myself but I would sooner you 【go】.
49.While 【attempted】to reach his home before the storm,John had an accident on his bicycle.
50.Few people realize that how essential health is to a normal life until 【we】 are seriously ill.