答案：helping
翻译：你永远想象不到我在帮助受伤严重的贫困男孩的时候有多大麻烦.
解析：考察固定句型：have trouble/difficulty (in) doing sth 做某事有麻烦/困难.
what great trouble I had 正常语序就是 I had what great trouble ,符合这个句型.