Опять прошу Вас посодействовать:)1. Kate missed the film last nght, because

Вновь прошу Вас помочь:)
1. Kate missed the film last nght, because she___ work late.
a) had to
b) can
c) could
d) may
2. It is only ten a.m. She___ at school now.
a) must be
b) should have been
c) could be
d) have be
3. He'll be fired if he ___ improve his work.
a) doesn't
b) will
c) won't
d) has to
4. Please do nor speak to anyone before the police___.
a) come
b) are coming
c) 'll come
d) came
5. Mary ___ pass the English exam yesterday, because she fell ill the flu.
a) could
b) mustn't
c) didn't have to
d) wasn't able to
Спасибо великое! =)