In the fall， not only did the cows have to be milked， but also the hay was mowed and stacked by my grandfather"s family.
本句不够简洁的原因是本句的重心应该是“忙碌的家庭-my grandfather"s family”，而使用了被动语态后，仿佛重心变成了cows和hay。下面的表达方式是主动语态，相对来说更简洁一些：
In the fall， my grandfather"s family not only milked the cow but also mowed and stacked the hay.
The situation that resulted in my grandfather"s not being able to study engineering was that his father needed help on the farm.
从意思上来分析，上面这句话需要表达的重要的概念是“grandfather"s not being able to study”，而在表达这个概念时，原句用的主语是situation，谓语动词是was，不能强调需要表达的重点概念，可以改为下面这句话：
My grandfather couldn"t study engineering because his father needed help on the farm.
3. 避免频繁使用“there be”结构。
There were 25 cows on the farm that my grandfather had to milk every day. It was hard work for my grandfather.
My grandfather worked hard. He had to milk 25 cows on the farm every day.
My grandfather worked hard milking 25 cows daily.
Dairy cows were raised on the farm，which was located100 kilometers from the nearest university and was in an area that was remote.
The dairy farm was located in a remote area， 100 kilometers tothe nearest university.
My grandfather didn"t have time to stand around doing nothing with his school friends.
Stand around doing nothing其实可以用一个动词来表达，即loiter：
My grandfather didn"t have time to loiter with his school friends.