投资回收期
参考答案：
投资回收期是衡量一个开发工程价值的经济指标。投资回收期就是积累的经济效益等于最初的投资所需要的时间。
根据句意和所给中文写出句中所缺的单词.
1. May I _____ (介绍) my best friend Amy to you, Sandy?
2. I think it's our _____ (职责) to protect the environment.
3. The cinema has _____ (出口) on its three sides.
4. Will you please pay _____ (注意力) to what I am saying?
5. How many _____ (客人) were there in yesterday's party?
在窗体上画一个命令按钮，然后编写如下事件过程： Private Sub Command_Click( ) S=0 Do s=(s + 1) * (s +2) Number=Number+1 Loop Until S＞=30 Print Number，S End Sub 程序运行后，输出的结果是()。
A． 2 3
B． 3 182
C． 5 12
D． 10 20
