某商店同时卖出两种商品，每种各得480元。其中一种赚20%，另一种亏20%。这个

In October 1987 the United States stock market suffered a major drop in prices. During the weeks after the drop, the volume of stocks traded also dropped sharply to well below what had been the weekly average for the preceding year.
However, the volume for the entire year was not appreciably different from the preceding year’s volume.
Which of the following, if true, resolves the apparent contradiction presented in the passage above ？（）

A．Foreign investors usually buy United States stocks only when prices are low.

B．The number of stock buyers in 1987 remained about the same as it had been the preceding year.

C．For some portion of 1987, the volume of stocks traded was higher than the average for that year.

D．The greater the volume of stocks traded in a given year, the lower the average price per share on the United States stock market for that year.

E．The volume of stocks traded rises and falls in predictable cycles.

建设工程质量问题出现偏差，有的发生轻度偏差，有的情况比较严重，有的是很严重。这就是风险中的( )。

A．不确定性
B．差异
C．识别
D．对策

有性生殖

下面哪项数值提示胎儿肾已成熟（）

A.孕妇尿中E／C比值>15

B.羊水中肌酐值≥3mg／dl

C.羊水中肌酐值≥176.8μmol／L

D.羊水中HPL值>4mg／L

E.羊水中肌酐值≥180.8μmol／L

在某公交线路上，共投入10辆营运车辆，线路长度为10公里，营运速度为20公里/小时，则行车间隔应为（）分/辆。

A．12 

B．10 

C．6 

D．4