诊断用X线机出现下列故障时，哪种情况还会有X线产生
A. X线管灯丝断路B．高压变压器断路
B. X线管焦点变形破损
C. X线管阳极侧高压电缆未接触
D. 灯丝变压器断路
查看答案
Mrs. Mary wore a string of beads around her neck（）
A. small pieces of gold
B. small balls of precious stones
C. small pieces of wood
D. small balls of glass
下列不属于X线管电参数的是
A. 最高管电压
B. 最大管电流
C. 最长曝光时间
D. 最大允许功率
E. 有效焦点尺寸
We met the young couple at a party three weeks ago.（）we've had no further communication.
A. Thereof
B. Thereby
C. Thereafter
D. Thereabouts
The United States Constitution provides for a count of the population（）a census, every ten years.
A. called
B. which called
C. that it is called
D. as called
微信支付 
支付宝支付