压井/井控程序设置的作用是（）。A、计算出压井数据、确定压井所需循环周期； B、计算

工作单签收时注意事项？

正位胸片上，Lutembacher综合征表现为

A．肺纹理增多

B．多数患者肺纹理正常

C．肺门影缩小

D．右心增大

E．左心房增大

如图甲所示，真空中的电极K连续不断地发出电子（设电子的初速度为零），经电压为U₁的电场加速，加速电压U₁随时间t变化的图象如图乙所示，电子在电场U₁中加速时间极短，可认为加速时电压不变，电子被加速后由小孔S穿出，沿两个彼此靠近的水平金属板A、B间中轴线从左边缘射入偏转电场，A、B极板长均为L=0.20m，两板之间距离d=0.05m，A板的电势比B板电势高，A、B板右侧边缘到竖直放置的荧光屏P之间的距离b=0.10m，荧光屏的中心O与A、B板的中心轴线在同一水平线上，求：

（1）当A、B板间所加电压U₂为多少时，电子恰好都打不到荧光屏上；

（2）当A、B板间所加电压U₂′=U₂/2时，可看到屏幕上电子条距中心O的范围．

哲学上的天人合一体现在以下哪种文献中？（）

A、《周易》

B、《大学》

C、《中庸》

D、《孟子》

In the United States in 1986, the average rate of violent crime in states with strict gun-control laws was 645 crimes per 100,000 persons—about 50 percent higher than the average rate in the eleven states where strict gun-control laws have never been passed. Thus one way to reduce violent crime is to repeal strict gun control laws.
Which of the following, if true, would most weaken the argument above

A．The annual rate of violent crime in states with strict guncontrol laws has decreased since the passage of those laws.

B．In states with strict gun-control laws, few individuals are prosecuted for violating such laws.

C．In states without strict gun-control laws, many individuals have had no formal training in the use of firearms.

D．The annual rate of nonviolent crime is lower in states with strict gun-control laws than in states without such laws.

E．(E) Less than half of the individuals who reside in states without strict gun-control laws own a gun.