Translate into English using your active Grammar.... (Вы могли бы и повторить) your question when they asked you to. (to repeat)
Translate into English using your active Grammar.... (И где он может быть гулять) since morning? (to walk)
... (Не может быть, чтобы они забыли) about it. (Start your sentence with 'They...' and use 'to forget')
... (Неужели они учат) Grammar for two hours? (to study)
She ... (может быть, выучила) all the rules. (to learn)