患者，女，48岁。患脑肿瘤，脑水肿，剧烈头痛，结膜水肿，呕吐，静脉输入甘露醇后，病情随着大量排尿而渐趋稳定。其尿量改变的主要机制是

A．血浆胶体渗透压降低
B．血浆晶体渗透压降低
C．小管液溶质浓度升高
D．集合管壁对水的通透性降低
E．以上均非

• (A) 条件(1)充分，但条件(2)不充分．
• (B) 条件(2)充分，但条件(1)不充分．
• (C) 条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．
• (D) 条件(1)充分，条件(2)也充分．
• (E) 条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．

During a five-day period, Monday through Friday, the average (arithmetic mean) high temperature was 86 degrees Fahrenheit. What was the high temperature on Friday
(1) The average high temperature for Monday through Thursday was 87 degrees Fahrenheit.
(2) The high temperature on Friday reduced the average high temperature for the week by 1 degree Fahrenheit.