―Where is Michael? I cannot find him anywhere.
―He ______ have been off long. I saw him study in the room just now.
A.shouldn't B.can't C.mustn't D.needn't
―Where is Michael? I cannot find him anywhere.
―He ______ have been off long. I saw him study in the room just now.
A.shouldn't B.can't C.mustn't D.needn't