下列属于电离辐射的是（）
A.无线电波
B.微波
C.红外线
D.X射线
E.可见光
参考答案：D
Never before ___________in greater need of technical experts than it is today.
A．has Shenyang been
B．Shenyang has been
C．was Shenyang
D．Shenyang was
论述本岗的岗位职责。
