早期的殖民掠夺对欧洲产生的最大影响是： [] A、增强了殖民国家的实力 B、满足

一个单项选择测验有48道题，每题有4个备选项。用α=0.05单侧检验的标准，至少答对多少道题成绩显著地优于单凭猜测( )

A．答对16题

B．答对17题

C．答对18题

D．答对19题

In your construction project, the CPI is 1.30 and SPI is 0.85. What could be the potential reason

A) A critical resource went on sick leave for a long period of time, which had not been anticipated earlier.
B) The Cost of raw materials required for construction increased 10%.
C) You had not taken into account inflation rate.
D) There was 4 days waiting time in the curing of cement, and work could not be done during that time.

下列哪种元素不是致癌物质？（）

A.氡

B.镭

C.铀

D.金

E.钴

晶体管式时间继电器是根据RC电路充放电原理获得延时动作的。

阀门保温在工程结算中是如何规定的？