在产品失效过程的不同阶段中，故障率最低且趋向常数的阶段是( )。
A．早期故障期
B．晚期故障期
C．偶发故障期
D．磨损故障期
参考答案：C
经直肠超声检查的目的，不包括（）。
A.发现膀胱三角区小肿瘤
B.检查盆腔病变
C.诊断精囊腺疾病
D.检查前列腺病变
E.区别膀胱内陈旧出血和结石
Now that she is out of a job, Lucy _____ going back to school, but she hasn't decided yet.[ ]
A. had considered
B. has been considering
C. considered
D. is going to consider
