题干
— I phoned you yesterday morning. A girl answered, but I didn’t recognize the voice.
— Oh, it ____ my younger sister. She was in my room at that moment.
— Oh, it ____ my younger sister. She was in my room at that moment.
A：must have bee
B：should have bee
C：could have bee
D：may have bee
答案(点此获取答案解析）
A
