题干
— Whose is this book written by Yang Jiang?
— Carol's favorite writer is Yang Jiang. It be hers.
A：mustn't
B：must
C：can't
D：can
答案(点此获取答案解析）
B
— Whose is this book written by Yang Jiang?
— Carol's favorite writer is Yang Jiang. It be hers.
A：mustn't
B：must
C：can't
D：can
,
(如右上图);当甲,乙行走的速度相同(不为零)时刻:
