下列各分子中，所有原子都满足最外层为8电子结构的是 A．H2O B．NH3 C．

两根一样长的绳子，第一根用去13厘米，第二根用去8厘米，都有剩余，余下的相比[ ]

A.第二根比第一根长5厘米

B.第一根比第二根长5厘米

C.一样长

D.不能确定哪根长

消防（）适用于高温有火焰灼伤危险场所防护。

An investor currently has a portfolio valued at $700 000. The investor’s objective is long-term growth, but the investor will need $ 30 000 by the end of the year to pay his son’s college tuition and another $10 000 by year-end for his annual vacation. The investor is considering three alternative portfolios.（）

A．portfolio

B．expected return

C．standard deviation of returns

D．

1

2

3

E．

8%

10%

14%

F．

10%

13%

22%

液面的测量分类有哪几种？

工程呼应批准的工程延期为多少天
2．根据项目的财务净现金流量判断该项目是否可行
3．计算项目的静态投资回收期。