Agatha didn't have a happy marriage vs. Agatha isn't have...

[Tortilla]

English Grammar Tests, Elementary Level

ESL/EFL Test #103 "Agatha Christie test questions", question 2

Agatha Christie ......... have a happy marriage.

(a) wasn't
(b) didn't
(c) isn't

English Grammar Tests, Elementary Level

ESL/EFL Test #103 "Agatha Christie test questions", answer 2

Agatha Christie didn't have a happy marriage.

Correct answer: (b) didn't

Your answer was: incorrect
Agatha Christie isn't have a happy marriage.
_________________________

why i cant use isn't?

Tortilla

[Mister Micawber]

.
Be is used in combination with other verbs only in the continuous aspect (Agatha Christie isn't having a happy marriage) and in the passive voice (Fun isn't often had by married men)
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber