跌落式熔断器运行与维护的主要内容包括：瓷件、安装状况、触头状况、活动部分的性能以及消

The nurse is providing breast cancer education at a community facility. The American Cancer Society recommends that women get mammograms

A. yearly after age 40.
B. after the birth of the first child and every 2 years thereafter.
C. after the first menstrual period and annually thereafter.
D. every 3 years between ages 20 and 40 and annually thereafter.

宋代的书法家中，号为“北宋四大家”的是

①苏轼②黄庭坚③米芾④蔡襄⑤赵孟頫[     ]

A．①②③④

B．①③④⑤

C．②③④⑤

D．①②④⑤

治疗阴虚火旺之郁证，应首选

A．二阴煎
B．滋水清肝饮
C．天王补心丹
D．左归丸
E．黄连阿胶汤

钢轨顶面擦伤，容许速度在120～160km/h的线路，深度超过（）时，为重伤钢轨。