题干
—__________ Mr．White was appointed director of our department.
—Then we have two Whites now including ___________ Mr．White, the doorkeeper.
—Then we have two Whites now including ___________ Mr．White, the doorkeeper.
A：The; a
B：A; the
C：A; 不填
D：不填; a
答案(点此获取答案解析）
C
养技术，将二倍体胡萝卜韧皮部的一些细胞进行离体培养，最终发育成完整的新植株（见下图）关于这一科学事实，下列叙述中错误的是
