____the morning of the second day of the meeting, Dr. Smith read his paper.

A．At

B．In

C．On

D．From

急性白血病引起出血的常见原因是( )

A．纤维蛋白溶解
B．凝血因子缺乏
C．白血病细胞浸润血管
D．弥散性血管内凝血
E．血小板减少