half way line

I was approximately half way down the road, where the park and ride is located, when I saw a huge aircraft about 200 ft in length emerge out of the clouds about 100 ft over the tree line.

我是大约在路上，那里的公园和乘坐的位置，当我看到一个大约200英尺长的巨大的飞机出现在约100英尺的树线从云层中一半。

Until this month, the poverty line has been calculated the same way for half a century.

到本月为止，关于贫困线的计算方式已经持续了一个世纪。

I need a way to use batch to look at every line of a text file, and delete half of the lines in that text file, choosing which lines to delete at random.

我需要一种方法来使用批处理来看看一个文本文件中的每一行，并删除一半的行中的文本文件，选择哪些行删除随机的。