He must earn money отрицательная прошедшая будущая вопросительная форма предложения
He must not earn money He did must earn money He will must earn money Must he earn money?
He mustn't earn money. Must he earn money? He had to earn money. He will have to earn money. модальный глагол must не имеет прош.и будущего времён.у него для этого есть эквиваленты