在细胞分裂过程中，细胞中最先进行分裂的结构是[ ]
A．细胞壁
B．细胞质
C．细胞膜
D．细胞核
答案：D
____ 202 km Shanghai-Hangzhou high-speed railway, with ____ design speed of 350 km per hour, began
its operation on Oct 26, 2010.[ ]
A. The; a
B. The; the
C. A; a
D. A; the
若抛物线y=x2+mx+n的顶点坐标为（-1，4），则m=______，n=______．
