问题补充:
--- Perhaps John’s not in. --- . Look, the light is on.
A. Yes, he can be at home.
B. No, he couldn’t go out
C. Yes, he must be at home
D. No, he needn’t go out
答案:
A. Yes, he can be at home.
B. No, he couldn’t go out
(答案→)C. Yes, he must be at home
D. No, he needn’t go out
解析:考查情态动词表推测。Yes, he is.“不,他在家。”;must表示肯定推测,意为“一定”。故选C。