【单选题】有关普通X线机管电压预示与补偿,下列说法正确的是
B.
管电压的预示是通过在高压初级电路中串联以电压表预示
C.
由于高压初级电路各元器件电阻的存在,在管电流减小时,高压初级电路会产生较大的电压降
D.
电阻式管电压补偿电路是利用电阻分压,KV表只测量高压初级端电压的一部分
【简答题】book1 unit13 task2 B New York City: trend of population growth is _____; percentage is _____%.
【简答题】Now you will hear an interview about preserving important life stories. Listen carefully and complete the answers to the following questions according to what you hear. u05_1.mp3: 1. What is StoryCorp...
【单选题】Now you will hear a passage. At the end of the passage, you will hear some questions. After you hear a question, choose the best answer from the four choices.
A.
She considers herself very special.
B.
She considers herself the same as others.
C.
She considers herself a confident woman.
D.
She considers herself an experienced doctor.
【单选题】Now you will hear a passage. At the end of the passage, you will hear some questions. After you hear a question, choose the best answer from the four choices.
A.
She lost an arm and a leg.
B.
She began to live a normal life.
C.
She moved to China with her family.
D.
She almost died from a serious disease.
【多选题】关于管路特性阻力,以下说法正确的是()。
A.
串联管路的总特性阻力系数大于任何一段分管段的特性阻力系数
B.
并联管路的总特性阻力系数小于任何一段分管段的特性阻力系数
【单选题】.在信息资源规划中,建立子系统—功能模块—程序模块模型,属于()。
【多选题】关于下列串联型控制器工作方式说法正确的有( )
D.
与并联型控制器的电路结构相似,区别仅仅是将开关器件S1由并联在太阳能电池输出端改为串联在蓄电池充电回路中。