Вопрос, который вызвал трудности

Помогите выполнить тест, пожалуйста.
1. You will... speak Spanish in another few months.
A can
В have
С be able to
D ought
2. I'd like ...skate.
A to can
В to be able to
С to have to
D could
3. Nobody answers the phone. They... be out.
A should
В would
С can
D must
4. I'm sorry. I... have phoned to tell you I was coming.
A should to
В ought to
С had to
D could
5. To ray mind, the government... take care of old people
A ought
В need to
С must
D may

Ответ экспертов Учись.Ru

Чтобы дать полноценный ответ, был привлечён специалист, который хорошо разбирается в теме.

После обсуждения с другими специалистами сервиса мы пришли к выводу, что правильный ответ на ваш вопрос будет звучать следующим образом:

1. You will... speak Spanish in another few months.
С be able to

2. I'd like ...skate. 
В to be able to

3. Nobody answers the phone. They... be out.
D must

4. I'm sorry. I... have phoned to tell you I was coming.
В ought to

5. To my mind, the government... take care of old people
С must