在何种情况下出现虚假水位？出现虚假水位时应如何控制汽包水位在正常范围内？

根据句意从括号中选择恰当的介词填空

1. I go to school __________(at / on) 7:30 every morning.

2. The doctor would like to meet her __________(between / among) 8:00 and 9:00 tomorrow morning.

3. -When did Hong Kong return to China?

    -__________(In / On) July 1st, 1997.

4. In the West, there is lots of excitement __________(in / on) Christmas morning when children get up

    very early to open their presents.

5. The Smiths have lived in China __________ (for / since) five years.

TCP是TCP/IP协议簇的传输层协议，其在互联网中使用的流量控制协议是 (13) 。

A．选择重发ARQ协议

B．后退N帧ARQ协议

C．超时重传和捎带确认协议

D．可变大小的滑动窗口协议

在风险管理过程中，“制定预防计划”的工作属于( )的内容。

A．风险识别

B．风险评价

C．风险对策决策

D．实施决策

连续博弈模型是指寡头垄断企业依次不断选择策略。

税源管理主要任务是什么？