（）对实时系统最重要。
A.及时性
B.交互性
C.共享性
D.运行效率
参考答案：A
—Shall I keep an eye on your house when you are on holiday?
—________.[ ]
A. It's up to you
B. Of course,you should
C. If you like
D. I would appreciate that
椎弓峡部断裂，正确的摄影体位是
A．腰椎正位B．腰椎侧位C．腰椎双斜位D．腰骶部斜位E．腰骶部侧位
