$string = "<span style='position:absolute'>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua.</span> Ut enim ad minim veniam,
我无法弄清楚如何用正则表达式来做到这一点。我想在句子中的一定数量的字符后匹配句号。 this is a long sentence. it contains a few full stops in it. I want to match the full stop after the halfway point.
this sentence is shorter. it also contai