質問: what is the difference between あの人のかさを持って来てしまった and あの人のかさを持って来た ? what is the difference between あの人のかさを持って来てしまった and あの人のかさを持って来た ?
回答: @muffine in the first one, that person, unfortunately, brought with him an umbrella. the second one, he brought with him an umbrella. the しまった part means regret and such.