作业未完,机具未全部下道,线路未恢复到放行列车的条件时,不得撤除防护。
参考答案:对
Listen to the two girls by the window. What language _____?
A.did they speak
B.were they speaking
C.are they speaking
D.have they been speaking
在活体上可进行多种脑功能的研究()
A.头颅拍片
B.正电子发射断层扫描(PET)
C.电子计算机体层扫描摄影(CT)
D.磁共振成像(MRIMagneticResonanceImaging)
E.单光子发射计算机断层显像(SPECT)