—When _____ visit his aunt?
—Last weekend. [ ]
A. does she
B. do they
C. did he
D. did us
C
在危及()的建筑物、构筑物上,应根据航行要求设置障碍照明。
A.交通安全
B.作业安全
C.航行安全
D.疏散安全
加速器剂量监测仪线性允许精度是()
A.1.0%
B.1.5%
C.2.0%
D.2.5%
E.3.0%