Question

Their house . . . be haunted ; they have lived there for several years and they have never seen anything unusual. can’t may mustn’t must

Answer 1

Ответ:

Their house can't be haunted ; they have lived there for several years and they have never seen anything unusual.

Объяснение:

Поскольку они жили и не замечали ничего особенного, в доме не может быть привидений. Сразу же фокусируем внимание на отрицательные формы. Их у нас две: can't и mustn't. Для обозначения невероятности чего-либо, предпочтительно can't (mustn't возможно, но характерно для American English). Потому, мой ответ: can't

Answer 2

In the given sentence, the correct modal verb to use is "may."

"Their house may be haunted; they have lived there for several years and they have never seen anything unusual."

The modal verb "may" is used to express possibility or uncertainty. It suggests that there is a chance or possibility that their house is haunted, despite them not having seen anything unusual in all the years they have lived there.