潮气量(VT)正常值为()
A.200~300ml
B.300~400ml
C.400~500ml
D.500~600ml
E.600~700ml
参考答案:C
用适当的介词填一填。
1. A postcard has a picture __________ it.
2. Please send the postcard __________ Li Ming __________ Thursday.
3. I have a picture __________ my family.
4. Danny sits down __________ Jenny's left.
不是旋转阳极控制电路特点的是()
A.高电压启动,低电压维持运转
B.有一定延迟时间来保证转子全速运转后曝光
C.设置保护电路,转子未转或转速达不到时不曝光
D.刹车电路
E.透视时旋转阳极也必须转动