"战地"在英文中可以翻译为"battlefield"或"war zone"。"公里"在英文中可以翻译为"kilometer"，复数形式为"kilometers"。

因此，"战地多少公里"可以用英文表达为"How many kilometers is the battlefield?"或"What is the distance of the war zone in kilometers?"

一些英文例句及其中文翻译如下：

"The battlefield is about 10 kilometers away from here." (战地离这里大约有10公里远。)
"It's hard to estimate the exact distance of the war zone, but it's pkely to be several kilometers wide." (很难估算战区的准确距离，但可能有几公里宽。)
"The battlefield was several kilometers in length and width." (战场有几公里长和宽。)

来源：英语是世界上广泛使用的语言之一，"kilometer"和"battlefield"均为英语中常用的词汇。