▲during与while的区别主要在词性。虽然它们在意思上有相似之处，但它们的词性不同：during 是介词，用于引出介词短语；while是连词，用于引导时间状语从句。你的句子意思是：While she was in prison, friends used to bring her books and writing materials. 她在狱中时经常有朋友给她带书去。

▲during引导的介词短语：

During this past week, temperatures have fluctuated 50 degrees. 在过去这周里，温度波动达50度。

During his lifetime, he experienced two world wars and the Great Depression. 他一生种经历了两次世界大战和大萧条。

During our walk in the woods, we got lost and had to orient ourselves with a compass. 我们在树林中散步的时候迷路了，只好用指南针来确定我们的位置。

▲while引导的时间状语从句：

While I’m out, you can meantime do the dishes. 在我外出时，你可以把碗洗了。

While everyone was dancing we slipped away and went home. 大家在跳舞的时候，我们悄悄溜回家。

While we are away in the summer, our neighbor forwards our mail to us. 我们夏天不在家时，我们的邻居会把信件转交给我们。

▲while引导时间状语从句时，若主从句主语相同，且从句谓语含有动词be，则通常可省略从句的主语和动词be：

While abroad, we read about problems at home. 在国外时，我们通过阅读了解国内的问题。(=While we were abroad…)

While waiting for the plane, they passed the time playing games with the children. 候机时他们跟孩子们做游戏来打发时间。(=While they were waiting…)

比较：

While sleeping, our spine no longer needs to support the weight of our body. 睡觉时，我们的脊柱不用再支撑我们的身体。