Modal verbs past form

( It is not possible that Jane knew about my birthday party . )
Jane ____________________ ____________________ ____________________ about my birthday part y

( I'm certain that Joseph was responsible for the mistake . )
Joseph ____________________ ____________________ ____________________ responsible for the mistake .

( It is possible that Andrew did not hear the news about his brother . )
Andrew ____________________ ____________________ ____________________ ____________________ the news about his brother .

( It is strange that nobody called me yesterday . )
Somebody ____________________ ____________________ ____________________ me yesterday .

( It is impossible that you saw me last weekend . I was on holiday . )
You ____________________ ____________________ ____________________ me last weekend . I was on holiday .

( I'm sure the politician knew that he was going to lose the election . )
The politician ____________________ ____________________ ____________________ that he was going to lose the election .

( It is strange that it was so cold last month . Normally August is a very hot month . )
It ____________________ ____________________ ____________________ so cold in August .

( Her Russian is excellent . It is possible that she had a very good teacher . )
She ____________________ ____________________ ____________________ a very good teacher .