Задать вопрос: he went to london last summer.

Есть 5 видов вопросов:
Did he go to London last summer? - общий
He went to London last summer, didn't he? - разделительный
Who went to London last summer? - к подлежащему
Where did he go last summer? - специальный
Did he go to London or Berlin last summer? - альтернативный

Did he go to London last summer? Where did he go last summer? When did he go to London? Можно задать эти три вопроса, не знаю какой нужен тебе)