题干
Who's that man? ________.( )
A：She is my mother.
B：He is my father.
C：This is a book.
答案(点此获取答案解析）
B
Who's that man? ________.( )
A：She is my mother.
B：He is my father.
C：This is a book.
是方程
的一组解，则a的值（ ）