从事特种作业的劳动者必须经过专门培训并取得()证书。
参考答案:特种作业资格
As the busiest woman in the village, she made _____ her duty to look after all the other people’s affairs in that village.
A.this
B.that
C.one
D.it
作为X线照片影像的可供诊断的密度范围是()
A.0.5~1.0
B.0.5~2.0
C.0.25~2.0
D.0.25~2.5
E.0.5~2.5