for
意义上没有区别但是后面跟的内容有区别
get ready to后面加动词原形 也就是get ready to do sth.
get ready for后面加ING格式或者名词 也就是get ready for doing sth.或者get ready for sth.
举几个例子：
get ready to have a picnic
get ready for having a picnic
get ready for a picnic